GM Firebird 1982-1992 Repair Guide

Carburetors

Print

The V6 engine is equipped with the Rochester E2SE carburetor, V8 engines use the E4ME and E4MC. These carburetors are of the downdraft design and are used in conjunction with the CCC system for fuel control. They have special design features for optimum air/fuel mixture control during all ranges of engine operation.

An electric solenoid in the carburetor controls the air/fuel ratio. The solenoid is connected to an Electronic Control Module (ECM) which is an on-board computer. The ECM provides a controlling signal to the solenoid. The solenoid controls the metering rod(s) and an idle air bleed valve, thereby closely controlling the air/fuel ratio throughout the operating range of the engine.

MODEL IDENTIFICATION



General Motors Rochester carburetors are identified by their model code. The first number indicates the number of barrels, while one of the last letters indicates the type of choke used. These are V for the manifold mounted choke coil, C for the choke coil mounted in the carburetor body, and E for electric choke, also mounted on the carburetor. Model codes ending in A indicate an altitude-compensating carburetor.

Because of their intricate nature and computer controls, the E2SE, E4ME and E4MC carburetors should only be serviced by a qualified technician.

PRELIMINARY CHECKS



The following should be observed before attempting any adjustments.

  1. Thoroughly warm the engine. If the engine is cold, be sure that it reaches operating temperature.
  2.  
  3. Check the torque of all carburetor mounting nuts and assembly screws. Also check the intake manifold-to-cylinder head bolts. If air is leaking at any of these points, any attempts at adjustment will inevitably lead to frustration.
  4.  
  5. Check the manifold heat control valve (if used) to be sure that it is free.
  6.  
  7. Check and adjust the choke as necessary.
  8.  
  9. Adjust the idle speed and mixture. If the mixture screws are capped, don't adjust them unless all other causes of rough idle have been eliminated. If any adjustments are performed that might possibly change the idle speed or mixture, adjust the idle and mixture again when you are finished.
  10.  

Before you make any carburetor adjustments make sure that the engine is in tune. Many problems which are thought to be carburetor related can be traced to an engine which is simply out-of-tune. Any trouble in these areas will have symptoms like those of carburetor problems.

ADJUSTMENTS



Fast Idle
ROCHESTER E2SE
  1. Refer to the emission label and prepare the vehicle for adjustment.
  2.  
  3. Place the fast idle screw on the highest step of the fast idle cam.
  4.  
  5. Turn the fast idle screw to obtain the fast idle speed.
  6.  

ROCHESTER E4ME AND E4MC

The fast idle adjustment must be performed according to the directions of the emissions label.

Float and Fuel Level

See Figures 1 and 2

ROCHESTER E2SE
  1. Remove the air horn and gasket.
  2.  
  3. While holding the retainer in place, push the float down lightly against the needle.
  4.  
  5. Place a measuring gauge on the float at the farthest point from the float hinge.
  6.  
  7. To adjust, remove the float and bend the arm up or down. Also check the float alignment.
  8.  
  9. Install the air horn and gasket.
  10.  



Click image to see an enlarged view

Fig. Fig. 1: Float adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. Remove the air horn and gasket from the float bowl. Hold the float retainer down firmly. Push the float down (lightly) against the needle.
  2.  
  3. Position a T-scale over the toe of the float 1 / 16 in. (1.6mm) from the end of the float toe.
  4.  
  5. If the float level varies more than 1 / 16 in. (1.6mm) from the specified setting, it must be reset.
  6.  



Click image to see an enlarged view

Fig. Fig. 2: E4ME/E4MC float level adjustment

FLOAT LEVEL TOO HIGH
  1. Hold the float retainer in place.
  2.  
  3. Push down on the center of the float until the correct level is obtained.
  4.  

FLOAT LEVEL TOO LOW
  1. Lift out the metering rods and remove the solenoid connector screws.
  2.  
  3. Turn the lean mixture solenoid screw clockwise, counting and recording the number of turns required to seat the screw in the float bowl.
  4.  
  5. Turn the screw counterclockwise and remove it. Lift the solenoid and the connector from the float bowl.
  6.  
  7. Remove the float and bend the arm up to adjust. The float must be correctly aligned after adjustment.
  8.  
  9. To install the components, reverse the order of removal. Back out the solenoid mixture screw the number of turns that was recorded earlier.
  10.  

Throttle Linkage

ROCHESTER E2SE

No adjustment of the throttle cable can be made.

ROCHESTER E4ME AND E4MC

Due to the design of the throttle cable, no adjustments of the throttle linkage can be made.

Choke Unloader (Primary)

See Figures 3, 4 and 5

ROCHESTER E2SE
  1. Connect a rubber band to the intermediate choke lever and open the throttle to allow the choke valve to close.
  2.  
  3. Set up the angle gauge and set the gauge to specifications.
  4.  
  5. Using a vacuum source, retract the vacuum break plunger. Make sure that the air valve rod does not interfere with the retraction of the vacuum break plunger.
  6.  
  7. Support the vacuum break rod and make the adjustment by bending the rod.
  8.  



Click image to see an enlarged view

Fig. Fig. 3: Primary vacuum break adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. Connect a rubber band to the green tang of the intermediate choke shaft.
  2.  
  3. Open the throttle to allow the choke valve to close.
  4.  
  5. Set up the angle gauge and set to specifications.
  6.  
  7. Using a vacuum source, retract the vacuum break plunger. The air valve rod must not restrict the breaker plunger from fully retracting.
  8.  
  9. With the vacuum applied, turn the adjusting screw until the centering bubble of the angle gauge is level.
  10.  



Click image to see an enlarged view

Fig. Fig. 4: Primary vacuum break adjustment on E4ME/E4MC carburetors



Click image to see an enlarged view

Fig. Fig. 5: Vacuum break adjustment information

Choke Unloader (Secondary)

See Figures 6 and 7

ROCHESTER E2SE
  1. Connect a rubber band to the intermediate choke lever and open the throttle to allow the choke to close.
  2.  
  3. Set up the angle gauge and set the angle to specifications.
  4.  
  5. Using a vacuum source, retract the vacuum break plunger and retain the vacuum pressure.
  6.  
  7. Refer to the accompanying illustration to perform this procedure. Center the angle gauge bubble by turning an 1 / 8 in. (3mm) Allen wrench or bending vacuum break rod.
  8.  



Click image to see an enlarged view

Fig. Fig. 6: Secondary vacuum break adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. Connect a rubber band to the green tang of the intermediate choke shaft.
  2.  
  3. Open the throttle to allow the choke valve to close.
  4.  
  5. Set up the angle gauge and set the angle to specification.
  6.  
  7. Using a vacuum source, retract the vacuum break plunger.
  8.  

The air valve rod must not restrict the vacuum break plunger from fully retracting.

  1. With the vacuum applied, turn the adjusting screw or bend the vacuum break rod until the bubble of the angle gauge is centered.
  2.  



Click image to see an enlarged view

Fig. Fig. 7: Secondary vacuum break adjustment on E4ME/E4MC carburetors

Air Valve Spring Adjustment

See Figures 8 and 9

ROCHESTER E2SE
  1. If necessary, remove the intermediate choke rod to gain access to the lock screw.
  2.  
  3. Loosen the lock screw and turn the tension adjusting screw clockwise until the air valve opens slightly.
  4.  
  5. Turn the adjusting screw counterclockwise until the air valve just closes; continue turning the screw counterclockwise according to specifications.
  6.  
  7. Tighten the lock screw. Apply lithium grease to the spring and pin.
  8.  



Click image to see an enlarged view

Fig. Fig. 8: Air valve spring adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. Loosen the lock screw and turn the tension adjusting screw counterclockwise until the air valve partly opens.
  2.  
  3. Turn the tension adjusting screw clockwise until the air valve just closes, then turn the screw clockwise a specified number of turns.
  4.  
  5. Tighten the lock screw and apply lithium grease to the spring contact area.
  6.  



Click image to see an enlarged view

Fig. Fig. 9: Air valve spring adjustment on E4ME/E4MC carburetors

Air Valve Rod Adjustment

See Figures 10, 11 and 12

ROCHESTER E2SE
  1. Set up the angle gauge on the air valve and set the angle to specification.
  2.  
  3. Use a vacuum source to seat the vacuum break plunger.
  4.  
  5. By applying light pressure to the air valve lever, rotate it in the opening direction.
  6.  
  7. Support the air valve rod and bend it to make the adjustment.
  8.  



Click image to see an enlarged view

Fig. Fig. 10: Air valve rod adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. Using a vacuum source, seat the vacuum break plunger. The air valve must be closed.
  2.  
  3. Insert a 0.025 in. (0.635mm) plug gauge between the rod and the end of the slot.
  4.  
  5. To adjust, bend the air valve rod.
  6.  



Click image to see an enlarged view

Fig. Fig. 11: Front air valve rod adjustment on E4ME/E4MC carburetors



Click image to see an enlarged view

Fig. Fig. 12: Rear air valve rod adjustment on E4ME/E4MC carburetors

Choke Lever Adjustment

See Figures 13 and 14

ROCHESTER E2SE
  1. If the choke cover is riveted, drill out the rivets and remove the choke cover with the spring assembly.
  2.  
  3. Place the fast idle screw on the high step of the fast idle cam. Push the intermediate choke lever until the choke valve is closed.
  4.  
  5. Place a 0.085 in. (2.16mm) plug gauge in the choke housing hole and move the choke lever to touch the plug gauge.
  6.  
  7. Support the intermediate choke rod and bend it to make adjustment.
  8.  
  9. To install choke cover, use pop rivets.
  10.  



Click image to see an enlarged view

Fig. Fig. 13: Choke lever adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. If the choke cover plate is riveted, drill out the rivets and remove the plate assembly.
  2.  
  3. Place the fast idle cam follower on the high step of the fast idle cam.
  4.  
  5. Lift up on the choke lever to close the choke valve and insert a 0.120 in. (3mm) plug gauge into the choke housing hole. The choke lever should just touch the gauge.
  6.  
  7. To adjust, bend the choke rod.
  8.  
  9. To replace the cover plate, rivet in place.
  10.  



Click image to see an enlarged view

Fig. Fig. 14: Choke lever adjustment on E4ME/E4MC carburetors

Choke Rod Fast Idle Cam Adjustment

See Figures 15, 16 and 17

ROCHESTER E2SE
  1. Attach a rubber band to the intermediate choke lever and open the throttle to allow the choke plate to close.
  2.  
  3. Set up the angle gauge and set the angle to specifications.
  4.  
  5. Place the fast idle screw on the second step of the cam, against the high step.
  6.  
  7. Move the choke shaft lever, to open the choke valve, make contact with the black closing tang.
  8.  
  9. Support the fast idle cam rod and bend the rod to make the adjustment. Adjustment is completed when the bubble of the angle gauge is level.
  10.  



Click image to see an enlarged view

Fig. Fig. 15: Choke rod fast idle cam adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. Connect a rubber band to the green tang of the intermediate choke shaft.
  2.  
  3. Open the throttle to allow the choke valve to close.
  4.  
  5. Set up the angle gauge and set the angle to specifications.
  6.  
  7. Place the cam follower on the second step of the fast idle cam, against the rise of the first step. If the cam follower does not contact the cam, turn the fast idle screw additional turns.
  8.  
  9. To adjust, bend the tang of the fast idle cam until the gauge bubble is centered.
  10.  

The final fast idle speed adjustment must be performed according to the emission control label.

Click image to see an enlarged view

Fig. Fig. 16: Choke valve angle gauge



Click image to see an enlarged view

Fig. Fig. 17: Choke rod fast idle cam adjustment on E4ME/E4MC carburetors

Unloader Adjustment

See Figures 18 and 19

ROCHESTER E2SE
  1. Connect a rubber band to the intermediate choke lever and open throttle to allow the choke to close.
  2.  
  3. Set up the angle gauge and set the angle to specifications.
  4.  
  5. Hold the throttle lever in wide-open position and push on the choke lever to open the choke, making contact with the black closing tang.
  6.  
  7. To adjust, bend the tang until the bubble of the angle gauge is centered.
  8.  



Click image to see an enlarged view

Fig. Fig. 18: Unloader adjustment on E2SE

ROCHESTER E4ME AND E4MC
  1. Connect a rubber band to the green tang of the intermediate shaft.
  2.  
  3. Open the throttle to allow the choke valve to close.
  4.  
  5. Set up the angle gauge and set the angle to specification.
  6.  
  7. Hold the secondary lockout lever away from the pin.
  8.  
  9. Hold the throttle lever in the wide-open position.
  10.  
  11. To adjust, bend the tang of the fast idle lever until the bubble of the angle gauge is centered.
  12.  



Click image to see an enlarged view

Fig. Fig. 19: Unloader adjustment on E4ME/E4MC

Secondary Lockout Adjustment

See Figures 20 and 21

ROCHESTER E2SE
  1. Push down on the intermediate choke lever to hold the choke valve wide-open.
  2.  
  3. Open the throttle lever until the end of the secondary actuating lever is opposite the toe of the lockout lever.
  4.  
  5. Insert a 0.025 in. (0.635mm) plug gauge.
  6.  
  7. To adjust, bend the lockout lever tang into contact with the fast idle cam.
  8.  



Click image to see an enlarged view

Fig. Fig. 20: Secondary lockout adjustment on E2SE carburetors

ROCHESTER E4ME AND E4MC
  1. With the choke and the throttle valves closed, insert a 0.015 in. (0.38mm) plug gauge between the lockout lever and the pin. To establish clearance, bend the pin.
  2.  
  3. Push down on the fast idle cam and hold the choke valve wide open.
  4.  
  5. Insert a 0.015 in. (0.38mm) plug gauge sideways between the lockout lever and the pin. To adjust, file the end of the pin.
  6.  



Click image to see an enlarged view

Fig. Fig. 21: Secondary lockout adjustment on E4ME/E4MC carburetors

Mixture Control (M/C) Solenoid

See Figures 22, 23, 24 and 25

TRAVEL TEST

These procedures are performed on four barrel models only. Before checking the mixture control solenoid travel, it may be necessary to modify the float gauge J-9789-130 or equivalent (used to externally check the float level).

This should be done by filing or grinding sufficient material off the gauge to allow for insertion down the vertical D-shaped hole in the air horn casting (located next to the idle air bleed valve cover).

Check that the gauge freely enters the D-shaped vent hole and does not bind. The gauge will also be used to determine the total mixture control solenoid travel.

With the engine OFF and the air cleaner removed, measure the control solenoid travel as follows:

  1. Insert a modified float gauge J-9789-130 or equivalent down the D-shaped vent hole. Press down on the gauge and release it.
  2.  
  3. Observe that the gauge moves freely and does not bind. With the gauge released (solenoid in the up position), be sure to read it at eye level and record the mark on the gauge (in inches/millimeters) that lines up with the top of the air horn casting (upper edge).
  4.  
  5. Lightly press down on the gauge until bottomed (solenoid in the down position). Record (in inches/millimeters) the mark on the gauge that lines up with the top of the air horn casting.
  6.  
  7. Subtract the gauge up dimension from gauge dimension. Record the difference (in inches/millimeters). This difference is total solenoid travel.
  8.  
  9. If total solenoid travel is not within 3 / 32 - 5 / 32 in. (2.4-3.9mm), perform the mixture control solenoid adjustments. If the difference is within specifications, proceed to the idle air bleed valve adjustment.
  10.  

If adjustment is required, it will be necessary to remove the air horn and drive out the mixture control solenoid screw plug from the under side of the air horn.

Click image to see an enlarged view

Fig. Fig. 22: Checking the solenoid plunger travel

ADJUSTMENTS

Before making adjustment to mixture control solenoid, verify that the plunger travel is not correct.

  1. Remove air horn, mixture control solenoid plunger, air horn gasket and plastic filler block, using normal service procedures.
  2.  
  3. Check carburetor for cause of incorrect mixture:
    1. M/C solenoid bore or plunger worn or sticking
    2.  
    3. Metering rods for incorrect part number, sticking or rods or springs not installed properly
    4.  
    5. Foreign material in jets
    6.  

  4.  
  5. Remove throttle side metering rod. Install mixture control solenoid gauging tool, J-33815-1, BT-8253-A, or equivalent, over the throttle side metering jet rod guide and temporarily reinstall the solenoid plunger into the solenoid body.
  6.  
  7. Holding the solenoid plunger in the DOWN position, use tool J-28696-10, BT-7928, or equivalent, to turn lean mixture solenoid screw counterclockwise until the plunger breaks contact with the gauging tool. Turn slowly clockwise until the plunger makes contact with the gauging tool. The adjustment is correct when the solenoid plunger is contacting both the solenoid stop and the gauging tool.
  8.  

If the total difference in adjustment required less than3/4turn of the lean mixture solenoid screw, the original setting was within the manufacturer's specifications.

  1. Remove solenoid plunger and gauging tool and reinstall metering rod and plastic filler block.
  2.  
  3. Invert air horn and remove rich mixture stop screw from bottom side of air horn, using tool J-28696-4, BT-7967-A, or equivalent.
  4.  
  5. Remove lean mixture screw plug and the rich mixture stop screw plug from air horn, using a punch.
  6.  
  7. Reinstall rich mixture stop screw in air horn and bottom lightly, then back screw out 1 / 4 turn.
  8.  
  9. Reinstall air horn gasket, mixture control solenoid plunger and air horn to carburetor.
  10.  
  11. Adjust the M/C solenoid plunger travel as follows:
    1. Insert float gauge down D-shaped vent hole. Press down on gauge and release, observing that the gauge moves freely and does not bind. With gauge released, (plunger UP position), read at eye level and record the reading of the gauge mark (in inches/millimeters) that lines up with the top of air horn casting, (upper edge).
    2.  
    3. Lightly press down on gauge until bottomed, (plunger DOWN position). Read and record (in inches/millimeters) the reading of the gauge mark that lines up with top of air horn casting.
    4.  
    5. Subtract gauge UP position from the gauge DOWN position and record the difference. This difference is the total plunger travel. Insert external float gauge in vent hole and, with tool J-28696-10, BT-7928, or equivalent, adjust rich mixture stop screw to obtain 5 / 32 in. (3.9mm) total plunger travel.
    6.  

  12.  
  13. With solenoid plunger travel correctly set, install plugs (supplied in service kits) in the air horn, as follows:
    1. Install plug, hollow end down, into the access hole for the lean mixture (solenoid) screw. Use suitably sized punch to drive plug into the air horn until the top of plug is even with the lower. Plug must be installed to retain the screw setting and to prevent fuel vapor loss.
    2.  
    3. Install plug, with hollow end down, over the rich mixture stop screw access hole and drive plug into place so that the top of the plug is 3 / 16 in. (4.7mm) below the surface of the air horn casting.
    4.  

  14.  

Plug must be installed to retain screw setting.

  1. To check the M/C solenoid dwell, first disconnect vacuum line to the canister purge valve and plug it. Ground diagnostic TEST terminal and run engine until it is at normal operation temperature (upper radiator hose hot) and in closed loop.
  2.  
  3. Check M/C dwell at 3000 rpm. If within 10-50 degrees, calibration is complete. If higher than 50 degrees, check the carburetor for a cause of rich condition. If below 10 degrees, look for a cause of lean engine condition such as vacuum leaks. If none are found, check for the cause of a lean carburetor.
  4.  



Click image to see an enlarged view

Fig. Fig. 23: Installing the mixture control solenoid gauging tool



Click image to see an enlarged view

Fig. Fig. 24: Adjusting the lean mixture solenoid screw



Click image to see an enlarged view

Fig. Fig. 25: Adjusting the rich mixture stop screw

Idle Air Valve

See Figures 26 and 27

A cover is in place over the idle air bleed valve. Also, the access holes to the idle mixture needles are sealed with hardened plugs. This is done to seal the factory settings, during original equipment production. These items are NOT to be removed unless required for cleaning, part replacement, improper dwell readings or if the System Performance Check indicates the carburetor is the cause of the trouble.

ROCHESTER E4ME AND E4MC
  1. With engine OFF , cover the internal bowl vents and inlet to bleed valve and the carburetor air intakes with masking tape. This is done to prevent metal chips from entering.
  2.  
  3. Carefully drill rivet head of idle air bleed cover, with 0.110 in. (2.8mm) drill bit.
  4.  
  5. Remove rivet head and all pieces of rivet.
  6.  
  7. Lift cover off air bleed valve and blow out any metal shavings, or use a magnet to remove excess metal.
  8.  


CAUTION
Always wear eye protection when using compressed air.

  1. Remove masking tape.
  2.  
  3. Start engine and allow it to reach normal operating temperature.
  4.  
  5. Disconnect the vacuum hose from the canister purge valve and plug it.
  6.  
  7. While idling in D for automatic transmission or N for manual transmission, slowly turn the valve counterclockwise or clockwise, until the dwell reading varies within the 25-35 degree range, attempting to be as close to 30 degrees as possible.
  8.  

Perform this step carefully. The air bleed valve is very sensitive and should be turned in1/8turn increments only.

  1. If the dwell reading does not vary and is not within the 25-35 degree range, it will be necessary to remove the plugs and to adjust the idle mixture needles.
  2.  



Click image to see an enlarged view

Fig. Fig. 26: Installing the idle air bleed valve gauging tool



Click image to see an enlarged view

Fig. Fig. 27: Adjusting the idle air bleed valve

Idle Mixture

See Figures 28, 29 and 30

E2SE CARBURETORS
  1. Remove the carburetor from the engine.
  2.  
  3. Remove the plugs covering the idle mixture needles.
  4.  
  5. Turn the mixture needle in until slightly seated, then back it out 4 turns.
  6.  
  7. If the plug in the air horn covering the idle air bleed has been removed, replace the air horn. If the plug is still in place, do not remove it.
  8.  
  9. Remove the vent stack screen assembly to gain access to the lean mixture screw.
  10.  
  11. Using tool J-28696-10 or equivalent, turn the lean mixture screw in until lightly seated, then back out 2 1 / 2 turns.
  12.  
  13. Install the carburetor on the engine.
  14.  
  15. Disconnect the bowl vent line at the carburetor.
  16.  
  17. Disconnect the EGR hose and canister purge hose at the carburetor. Cap the ports on the carburetor.
  18.  
  19. Find the hose from port D of the carburetor to the temperature sensor and secondary vacuum break thermal vacuum switch. Disconnect and plug the vacuum hose going to the air cleaner.
  20.  
  21. Connect the positive lead of a dwell meter to the mixture control solenoid test lead (green connector). Connect the other lead to ground. Set the meter to the 6 cylinder position.
  22.  
  23. Run the engine on the high step of the fast idle cam until the cooling fan starts to cycle.
  24.  
  25. Run the engine at 3,000 rpm and adjust the lean mixture screw slowly. Allow the reading to stabilize, obtain an average dwell of 35 degrees. It is normal for the dwell to vary in a narrow range.
  26.  
  27. Return to idle.
  28.  
  29. Adjust the idle mixture screw to obtain an average dwell of 25 degrees. Allow time for the reading to stabilize.
  30.  
  31. Run the engine at 3,000 rpm and note the dwell reading. It should be varying with an average reading of 35 degrees. If it does not, repeat the earlier steps.
  32.  



Click image to see an enlarged view

Fig. Fig. 28: Idle mixture needle plug removal

E4ME CARBURETORS (ELECTRIC CHOKE)
  1. Using tool J-29030, BT-7610-B, or equivalent, turn both idle mixture needles clockwise until they are lightly seated, then turn each mixture needle counterclockwise 3 turns.
  2.  
  3. Reinstall carburetor on engine using a new flange mounting gasket, but do not install air cleaner and gasket at this time.
  4.  
  5. Disconnect the vacuum hose to canister purge valve and plug it. Readjust the idle air bleed valve to finalize correct dwell reading.
  6.  
  7. Connect the positive lead of a dwell meter to the mixture control solenoid test lead (green connector). Connect the other lead to ground. Set the meter to the 6 cylinder position.
  8.  
  9. Start engine and run until fully warm, then repeat the idle air bleed valve adjustment.
  10.  
  11. If unable to set dwell to 25-35 degrees and the dwell is below 25 degrees, turn both mixture needles counterclockwise an additional turn. If dwell is above 35 degrees, turn both mixture needles clockwise an additional turn. Readjust idle air bleed valve to obtain dwell limits. Repeat as needed.
  12.  
  13. After adjustments are complete, seal the idle mixture needle openings in the throttle body, using silicone sealant, RTV rubber, or equivalent. The sealer is required to discourage unnecessary adjustment of the setting and to prevent fuel vapor loss in that area. Reconnect canister vacuum hose.
  14.  
  15. On vehicles without an Idle Load Compensator (ILC), adjust curb idle speed if necessary.
  16.  
  17. Check, and if necessary, adjust fast idle speed as described on Vehicle Emission Control Information (VECI) label.
  18.  



Click image to see an enlarged view

Fig. Fig. 29: Lean mixture and idle mixture screw adjustment

E4MC CARBURETOR (HOT AIR CHOKE)
  1. Using tool J-29030-B, BT-7610-B, or equivalent, turn each idle mixture needle clockwise until lightly seated, then turn each mixture needle counterclockwise 3 turns.
  2.  
  3. Reinstall carburetor on engine, using a new flange mounting gasket, but do not install air cleaner or gasket at this time.
  4.  
  5. Disconnect vacuum hose to canister purge valve and plug it.
  6.  
  7. Connect the positive lead of a dwell meter to the mixture control solenoid test lead (green connector). Connect the other lead to ground. Set the meter to the 6 cylinder position.
  8.  
  9. Start engine and allow it to reach normal operating temperature.
  10.  
  11. While idling in D ( N for manual transmission), adjust both mixture needles equally, in 1 / 8 turn increments, until dwell reading varies within the 25-35 degree range, attempting to be as close to 30 degrees as possible.
  12.  
  13. If reading is too low, turn mixture needles counterclockwise. If reading is too high, turn mixture needles clockwise. Allow time for dwell reading to stabilize after each adjustment.
  14.  

After adjustments are complete, seal the idle mixture needle openings in the throttle body, using silicone sealant, RTV rubber, or equivalent. The sealer is required to discourage unnecessary readjustment of the setting and prevent fuel vapor loss in that area.

  1. On vehicles without a carburetor-mounted Idle Load Compensator (ILC) , adjust curb idle speed if necessary.
  2.  
  3. Check, and if necessary, adjust fast idle speed, as described on the Vehicle Emission Control Information (VECI) label.
  4.  



Click image to see an enlarged view

Fig. Fig. 30: Mixture needle and spring

Idle Load Compensator

See Figure 31

The idle load compensator is adjusted at the factory. Do not make any adjustments unless diagnosis leads to it, or curb idle speed is not to specification.

  1. Make certain ignition timing, mixture adjustment, vacuum hoses, fuel pressure and CCC system meets specifications.
  2.  
  3. Remove air cleaner and plug hose to thermal vacuum valve.
  4.  
  5. Connect a tachometer.
  6.  
  7. Disconnect and plug hose to EGR valve.
  8.  
  9. Disconnect and plug hose to canister purge port.
  10.  
  11. Disconnect and plug hose to idle load compensator.
  12.  
  13. Back out idle stop screw on carburetor 3 turns.
  14.  
  15. Turn air conditioning OFF.
  16.  
  17. Block drive wheels, set parking brake, place transmission in P , start and warm engine to normal operating temperature. Make certain choke is OPEN .
  18.  
  19. With engine RUNNING place transmission in D and idle load compensator fully extended (no vacuum applied). Using tool J-29607, or equivalent, adjust plunger to obtain 650-750 rpm. Locknut on plunger must be held with a wrench to prevent damage to guide tabs.
  20.  
  21. Measure distance from the locknut to tip of the plunger. This distance must not exceed 1 in. (25mm). If it does check for low idle condition.
  22.  
  23. Reconnect vacuum hose to idle load compensator and observe idle speed.
  24.  
  25. Idle speed should be between 425-475 rpm in D .
  26.  
  27. If idle speed is correct no further adjustment is necessary, proceed to the next step. If idle speed is still incorrect continue as follows:
  28.  

It may be necessary to remove the idle load compensator from the engine unless a hex key wrench is modified to clear obstructions.

    1. Stop engine, remove rubber cap from the center outlet tube.
    2.  
    3. Using a 0.90 in. (23mm) hex wrench, insert through open center tube to engage idle speed adjusting screw.
    4.  
    5. If idle speed was low, turn the adjusting screw counterclockwise approximately 1 turn for every 85 rpm low. If idle speed was high turn screw 1 turn for every 85 rpm high.
    6.  

  1. Disconnect and plug vacuum hose to the idle load compensator.
  2.  
  3. Using a hand pump, apply vacuum to the idle load compensator until fully retracted.
  4.  
  5. Adjust the idle stop screw on carburetor float bowl to obtain 450 rpm in D .
  6.  
  7. Place transmission in P and stop engine.
  8.  
  9. Reconnect the idle load compensator.
  10.  
  11. Reconnect all vacuum hoses.
  12.  
  13. Install air cleaner and gasket. Remove wheel blocks.
  14.  



Click image to see an enlarged view

Fig. Fig. 31: Idle load compensator components

Throttle Position Sensor (TPS)

See Figures 32 and 33

Before the throttle position sensor voltage output setting can be accurately checked or adjusted the idle rpm must be within specifications. The plug covering the TPS adjustment screw is used to provide a tamper-resistant design and retain the factory setting during vehicle operation. Do not remove the plug unless diagnosis indicates the TPS is not adjusted correctly, or it is necessary to replace the air horn assembly, float bowl, TPS, or TPS adjustment screw. This is a critical adjustment that must be performed accurately to ensure proper vehicle performance and control of exhaust emissions. Remove TPS plug if not already removed.

Adjustment is required only if voltage is above the following readings, as the ECM automatically zeros below 0.70 Volts.

  1. Using a 5 / 64 in. (2mm) drill bit, carefully drill a hole in the steel or aluminum plug. Be sure to drill only far enough to start a self tapping screw, the approximate drilling depth is 1 / 16 - 1 / 8 in. (1.6-3mm).
  2.  

Use care in drilling so as not to damage the TPS adjustment screw head.

  1. Start a long self tapping screw (No. 8 x 1 / 2 in.) into the drilled pilot hole in the plug. Turn the screw in only enough to ensure a good thread engagement in the drilled hole.
  2.  
  3. Place a suitable tool between the screw head and the air horn casting. Then pry against the screw head to remove the plug. A small slide hammer may also be used in this procedure. Be sure to discard the plug when it has been removed.
  4.  
  5. Connect a suitable digital voltmeter (J-29125 or equivalent) from the TPS connector center terminal (B) to the bottom terminal (C).
  6.  

Jumper wires for access can be made using terminals 12014836 and 12014837 or equivalent. Make jumper wires up with 16 gauge (1.0mm), 18 gauge (0.8mm) or 20 gauge (0.5mm) wire approximately 6 in. (152mm) long.

  1. With the ignition ON and the engine stopped, install the TPS adjustment screw and turn the screw with a suitable tool to obtain the specified voltage at the specified throttle position with the A/C controls in the OFF position.
    1. 2.8L - 0.30 volts at curb idle position
    2.  
    3. 5.0L - 0.40 volts at curb idle position
    4.  

  2.  
  3. After the adjustment has been made, install a new plug kit (supplied in the service kits), into the air horn. Drive the plug into place until it is flush with the raised pump lever boss on the casting. Clear trouble code memory after adjustment.
  4.  

The plug must be installed to retain the TPS adjustment screw setting. If a plug kit is not available, remove the TPS adjusting screw and apply thread sealer adhesive X-10 or equivalent to the screw threads. Now repeat the TPS adjustment procedure to obtain the correct TPS voltage.

Click image to see an enlarged view

Fig. Fig. 32: Throttle position sensor adjusting screw location on E2SE carburetors



Click image to see an enlarged view

Fig. Fig. 33: Throttle position sensor adjusting screw location on E4ME/E4MC carburetors

REMOVAL & INSTALLATION



See Figures 34 through 44

Always replace all internal gaskets that are removed. Flooding, stumble on acceleration and other performance complaints are in many instances, caused by presence of dirt, water, or other foreign matter in carburetor. To aid in diagnosis, carburetor should be carefully removed from engine without draining fuel from bowl. Contents of fuel bowl may then be examined for contamination as carburetor is disassembled. Check the fuel filter.

Rochester E2SE
  1. Remove air cleaner and gasket.
  2.  
  3. Disconnect fuel pipe and vacuum lines.
  4.  
  5. Disconnect electrical connectors.
  6.  
  7. Disconnect accelerator linkage.
  8.  
  9. If equipped with automatic transmission, disconnect downshift cable.
  10.  
  11. If equipped with cruise control, disconnect linkage.
  12.  
  13. Remove carburetor attaching bolts.
  14.  
  15. Remove carburetor and EFE heater/insulator (if used).
  16.  
  17. Inspect EFE heater/insulator for damage. Be certain throttle body and EFE heater/insulator surfaces are clean.
  18.  

To install:
  1. Install EFE heater/insulator.
  2.  
  3. Install carburetor and tighten nuts alternately to the correct torque.
  4.  
  5. Connect downshift cable, as required.
  6.  
  7. Attach the cruise control cable, as required.
  8.  
  9. Connect accelerator linkage.
  10.  
  11. Connect electrical connections.
  12.  
  13. Connect fuel pipe sand vacuum hoses.
  14.  
  15. Check base (slow) and fast idle.
  16.  
  17. Install the air cleaner.
  18.  



Click image to see an enlarged view

Fig. Fig. 34: Remove the air cleaner for access to the carburetor



Click image to see an enlarged view

Fig. Fig. 35: Use a back-up wrench when disconnecting fuel lines



Click image to see an enlarged view

Fig. Fig. 36: If the retaining clip on the connector is broken off like this one, it should be replaced



Click image to see an enlarged view

Fig. Fig. 37: The vacuum modulator line behind the carburetor must also be disconnected, if equipped



Click image to see an enlarged view

Fig. Fig. 38: The accelerator cable retaining clip can be removed using a pair of needle nose pliers



Click image to see an enlarged view

Fig. Fig. 39: The return spring and throttle valve cable must also be disconnected from the linkage



Click image to see an enlarged view

Fig. Fig. 40: Removing the rear carburetor attaching bolts (note: a long extension is helpful here)



Click image to see an enlarged view

Fig. Fig. 41: Removing the front carburetor attaching bolts



Click image to see an enlarged view

Fig. Fig. 42: Always replace this gasket anytime the carburetor is removed



Click image to see an enlarged view

Fig. Fig. 43: The emission hose routing sticker under the hood is helpful when installing the carburetor



Click image to see an enlarged view

Fig. Fig. 44: The adjustment specifications on the emission control information label must always be followed

Rochester E4ME and E4MC
  1. Disconnect the battery and remove the air cleaner.
  2.  
  3. Disconnect the accelerator linkage.
  4.  
  5. Disconnect the transmission detent cable.
  6.  
  7. If equipped, remove the cruise control cable.
  8.  
  9. Tag and detach all of the necessary vacuum lines and electrical connections.
  10.  
  11. Disconnect the fuel line at the carburetor inlet.
  12.  
  13. Remove the attaching bolts and remove the carburetor.
  14.  

To install:
  1. Position the carburetor onto the manifold and install the attaching bolts.
  2.  
  3. Connect the fuel line at the carburetor inlet.
  4.  
  5. Attach all of the vacuum lines and electrical connections, as tagged during removal.
  6.  
  7. If equipped, install the cruise control.
  8.  
  9. Connect the transmission detent cable.
  10.  
  11. Connect the accelerator linkage.
  12.  
  13. Install the air cleaner and connect the battery.
  14.  

OVERHAUL



Carburetor overhaul kits are recommended for each overhaul. These kits contain all gaskets and new parts to replace those which deteriorate most rapidly. Failure to replace all parts supplied with the kit (especially gaskets) can result in poor performance later.

Some carburetor manufacturers supply overhaul kits for three basic types: minor repair; major repair; and gasket kits. Certain parts may be expected in most kits based on the desired degree of overhaul.

Minor Repair Kits:


All gaskets
 
Float needle valve
 
All diaphragms
 
Spring for the pump diaphragm
 

Major Repair Kits:


All jets and gaskets
 
All diaphragms
 
Float needle valve
 
Pump ball valve
 
Float
 
Complete intermediate rod
 
Intermediate pump lever
 
Some cover hold-down screws and washers
 

Gasket kits:


All gaskets
 

Efficient carburetion depends greatly on careful cleaning and inspection during overhaul, since dirt, gum, water, or varnish in or on the carburetor parts are often responsible for poor performance.

Overhaul your carburetor in a clean, dust-free area. Carefully disassemble the carburetor, referring often to the exploded views and directions packaged with the rebuilding kit. Keep all similar and look-alike parts separated during disassembly and cleaning to avoid accidental interchange during assembly. Make a note of all jet sizes.

When the carburetor is disassembled, wash all parts (except diaphragms, electric components, pump plunger, and any other plastic, leather, fiber, or rubber parts) in clean carburetor solvent. Do not leave parts in the solvent any longer than is necessary to sufficiently loosen the deposits. Excessive cleaning may remove the special finish from the float bowl and choke valve bodies, leaving these parts unfit for service. Rinse all parts in clean solvent and blow them dry with compressed air or allow them to air dry. Wipe clean all cork, plastic, leather, and fiber parts with a clean, lint-free cloth.

Blow out all passages and jets with compressed air and be sure that there are no restrictions or blockages. Never use wire or similar tools to clean jets, fuel passages, or air bleeds. Clean all jets and valves separately to avoid accidental interchange.

Check all parts for wear or damage. If wear or damage is found, replace the defective parts. Especially check the following:

  1. Check the float needle and seat for wear.
  2.  
  3. Check the float hinge pin for wear and the float(s) for dents or distortion. Replace the float if fuel has leaked into it.
  4.  
  5. Check the throttle and choke shaft bores for wear or an out-of-round condition. Damage or wear to the throttle arm, shaft, or shaft bore will often require replacement of the throttle body. These parts require a close tolerance of fit; wear may allow air leakage, which could affect starting and idling.
  6.  

Throttle shafts and bushings are not included in overhaul kits. They can be purchased separately or repaired by a qualified carburetor overhaul shop.

  1. Inspect the idle mixture adjusting needles for burrs or grooves. Any such condition requires replacement of the needle, since you will not be able to obtain a satisfactory idle.
  2.  
  3. Test the accelerator pump check valves. They should pass air one way but not the other. Test for proper seating by blowing and sucking on the valve. Replace the valve check ball and spring as necessary. If the valve is satisfactory, wash the valve parts again to remove breath moisture.
  4.  
  5. Check the bowl cover for warped surfaces with a straightedge.
  6.  
  7. Closely inspect the accelerator pump plunger for wear and damage, replacing as necessary.
  8.  
  9. After the carburetor is assembled, check the choke valve for freedom of operation.
  10.  
  11. Check, repair or replace parts, if the following problems are encountered:
  12.  

Flooding



Inspect the float valve and seat for dirt, deep wear grooves, scores and improper sealing
 
Inspect the float valve pull clip for proper installation; be careful not to bend the pull clip
 
Inspect the float, the float arms and the hinge pin for distortion, binds, and burrs. Check the density of the material in the float; if heavier than normal, replace the float
 
Clean or replace the fuel inlet filter and check the valve assembly
 

Hesitation


Inspect the pump plunger for cracks, scores or cup excessive wear. A used pump cup will shrink when dry. If dried out, soak in fuel for 8 hours before testing
 
Inspect the pump duration and return springs for weakness or distortion
 
Check the pump passages and the jet(s) for dirt, improper seating of the discharge checkball or the temperature bypass disc and/or scores in the pumpwell. Check the condition of the pump discharge check ball spring, replace as necessary
 
Check the pump linkage for excessive wear; repair or replace as necessary
 

Hard Starting-Poor Cold Operation


Check the choke valve and linkage for excessive wear, binds or distortion
 
Test the vacuum break diaphragm(s) for leaks
 
Clean or replace the fuel filter
 
Inspect the float valve for sticking, dirt, etc.
 
Also check the items under "Flooding''
 

Poor Performance-Poor Gas Mileage


Clean all fuel and vacuum passages in the castings
 
Check the choke valve for freedom of movement
 
Check the Mixture Control (M/C) solenoid for sticking, binding or leaking
 
Check the air valve and secondary metering rod for binding conditions. If the air valve or metering rod is damaged or the metering rod adjustment is changed from the factory setting, the air horn assembly must be replaced. Also check the air valve lever spring for proper installation
 

Rough Idle


Inspect the gasket and gasket mating surfaces on the casting for nicks, burrs or damage to the sealing beads
 
Check the operation and sealing of the mixture control solenoid
 
Clean all of the idle field passages
 
If removed, inspect the idle mixture needle for ridges, burrs or being bent
 
Check the throttle lever and valves for binds, nicks. or other damage
 
Check all of the diaphragms for possible ruptures or leaks
 

After cleaning and checking all components, reassemble the carburetor, using new parts and referring to the exploded view. When reassembling, make sure that all screws and jets are tight in their seats, but do not overtighten as the tips will be distorted. Tighten all screws gradually, in rotation. Do not tighten needle valves into their seats; uneven jetting will result. Always use new gaskets. Be sure to follow all assembly and adjustment procedures.

Before performing any service on the carburetor, it is essential that it be placed on a suitable holding fixture, such as tool J-9789-118, BY-30-15 or equivalent. Without the use of the holding fixture, it is possible to damage throttle valves or other parts of the carburetor.

E2SE Disassembly

See Figures 45, 46, 47 and 48

SECONDARY VACUUM BREAK REMOVAL
  1. Remove the secondary vacuum break/bracket screw. Then, rotate the assembly to disengage the vacuum break link ("T" pin) from the choke lever slot.
  2.  

Do not immerse the idle speed solenoid or the vacuum break units in any type of carburetor cleaner. These items must always be removed before complete cleaning or damage to the components will result.

Click image to see an enlarged view

Fig. Fig. 45: Exploded view of the E2SE carburetor



Click image to see an enlarged view

Fig. Fig. 46: Component key list for the E2SE carburetor



Click image to see an enlarged view

Fig. Fig. 47: The carburetor must be placed on a holding fixture such as this one

AIR HORN REMOVAL
  1. Remove the clip from the hole in the pump rod.
  2.  

Do not remove the pump lever retaining screw or the pump lever from the air horn assembly.

  1. Remove and discard the retaining clip from the intermediate choke link at the choke lever. A new retaining clip is required for reassembly. Remove the choke link and the plastic bushing from the choke lever, then save the bushing for later re-use.
  2.  
  3. Remove the mixture control solenoid attaching screws; then, using a slight twisting motion, carefully lift the solenoid out of the air horn. Remove and discard the solenoid gasket.
  4.  
  5. Remove the seal retainer and the rubber seal from the end of the solenoid stem, being careful not to damage or nick the end of the solenoid stem. Discard the seal and retainer. Retain the spacer for use at time of reassembly.
  6.  
  7. Remove the air horn-to-fuel bowl screws and lockwashers.
  8.  
  9. Rotate the fast idle cam to the full UP position and remove the air horn assembly by tilting it to disengage the fast idle cam rod from the slot in the fast idle cam and the pump rod from the pump lever hole. If the pump plunger comes out of the float bowl during air horn removal, remove the pump plunger from the air horn. The air horn gasket should remain on the float bowl for removal later. Do not remove the fast idle cam screw and the cam from the float bowl. These parts are not serviced separately and are to remain permanently in place as installed by the factory. The new service replacement float bowl will include the secondary lockout lever, the fast idle cam and screw installed as required.
  10.  
  11. Remove the fast idle cam link from the choke lever by rotating the rod to align the upset on the link with the small slot in the lever.
  12.  

AIR HORN DISASSEMBLY
  1. Remove the Throttle Position Sensor (TPS) plunger by pushing it downward through the air horn seal.
  2.  

Use your fingers to remove the plunger. This will prevent damage to the sealing surface of the plunger.

  1. Remove the TPS and the pump plunger stem seals by inverting the air horn and using a small prytool to remove the staking, holding the seal retainer in place. Remove and discard the retainers and seals.
  2.  

Use care in removing the TPS plunger seal retainer and the pump plunger stem seal retainer to prevent damage to the air horn casting. New seals and retainers are required for reassembly.

  1. Remove the vent/screen assembly by removing the 2 small attaching screws.
  2.  
  3. Further disassembly of the air horn is not required for cleaning purposes or air horn replacement. A new service air horn assembly includes the secondary metering rod-air valve assembly with adjustments pre-set to factory specifications. No attempt should be made to change the air valve settings. The air valve and the choke valve attaching screws are staked in place and are not removable. A new service air horn assembly will also include a TPS adjustment screw. The new service air horn assembly will have the thermostatic pump bypass assembly installed, this temperature sensitive device is pressed permanently into place and is not serviceable, separately.
  4.  

FLOAT BOWL DISASSEMBLY
  1. Remove the air horn gasket.
  2.  
  3. Remove the pump plunger from the pump well, if not already removed with the air horn.
  4.  
  5. Remove the pump return spring from the pump well.
  6.  
  7. Push up from the bottom on the electrical connector and remove the Throttle Position Sensor (TPS) and the connector assembly from the float bowl. Remove the spring from the bottom of the TPS well in the bowl.
  8.  

Use care in removing the sensor and connector assembly to prevent damage to this critical electrical part.

  1. Remove the plastic filler block over the float valve.
  2.  
  3. Remove the float assembly and the float valve by pulling up the hinge pin (hold the float valve clip in place with your finger while tilting the float to clear the bowl vapor purge tube).
  4.  
  5. Using a removal tool or suitable prytool, remove the float valve seat (with gasket) and the extended metering jet from the float bowl.
  6.  

Do not remove or change the adjustment of the small calibration screw located deep inside the metering jet during routine servicing. The adjustment screw is pre-set at the factory and no attempt should be made to change this adjustment.

  1. Using a small slide hammer or equivalent, remove the plastic retainer holding the pump discharge spring and check ball in place. Discard the plastic retainer, a new retainer is required for reassembly.
  2.  

Do not attempt to remove the plastic retainer by prying it out with a tool such as a punch or screwdriver as this will damage the sealing beads on the bowl casting surface and require complete float bowl replacement. Turn the fuel bowl upside down catching the pump discharge spring and the check ball in palm of your hand. Return the bowl to the upright position.

  1. Remove the fuel inlet nut, the gasket, the check valve filter assembly and the spring.
  2.  

CHOKE DISASSEMBLY

A tamper resistant choke cover design is used to discourage readjustment of the choke thermostatic coil thermostatic coil assembly in the field. However, it is necessary to remove the cover and coil assembly during normal carburetor disassembly for cleaning and overhaul using the following procedures:

  1. Support the float bowl and the throttle body as an assembly on a suitable holding fixture.
  2.  
  3. Carefully align a No. 21 drill (0.159 in./4mm) on the rivet head and drill only enough to remove the rivet head. After removing the rivet heads and retainers, use a drift and a small hammer to drive the remainder of the rivets out of the choke housing.
  4.  

Use care in drilling to prevent damage to the choke cover or housing.

  1. Remove the screw from the end of the intermediate choke shaft inside the choke housing.
  2.  
  3. Remove the choke coil lever from the end of the shaft.
  4.  
  5. Remove the intermediate choke shaft assembly from the float bowl by sliding the shaft rearward and out of the throttle lever side.
  6.  
  7. Remove the choke housing by removing the 2 attaching screws.
  8.  



Click image to see an enlarged view

Fig. Fig. 48: Choke cover removal

THROTTLE BODY REMOVAL
  1. Remove the throttle body-to-bowl screws and the throttle body assembly from the float bowl.
  2.  
  3. Remove the throttle body gasket.
  4.  

THROTTLE BODY DISASSEMBLY
  1. Place the throttle body assembly on the carburetor holding fixture to avoid damaging the throttle valves.
  2.  
  3. Hold the primary throttle lever wide-open and disengage the pump rod from the throttle lever by rotating the rod until the upset on the rod aligns with the slot in the lever. Further disassembly of the throttle body is not required for cleaning purpose.
  4.  

The primary and secondary throttle valve screws are permanently staked in place and should not be removed. The throttle body is serviced as a complete assembly.

  1. Do not remove the plugs covering the idle mixture needle unless it is necessary to replace the mixture needle or normal soakings and air pressure fails to clean the idle mixture passages. If necessary, remove the idle mixture plug and needle as follows:
    1. Invert the throttle body and place it on a suitable holding fixture-manifold side up.
    2.  
    3. Make 2 parallel cuts into the throttle body on either side of the locator point beneath the idle mixture needle plug (manifold side) with a hacksaw. The cuts should reach down to the steel plug but should not extend more than 1.8 in. (46mm) beyond the locator point. The distance between the saw marks depends on the size of the punch to be used.
    4.  
    5. Place a flat punch at a point near the end of the saw marks in the throttle body. Holding the punch at a 45 degree angle, drive it into the throttle body until the casting breaks away, exposing the steel plug.
    6.  
    7. Holding a center punch vertical, drive it into the steel plug. Then holding the punch at a 45 degree angle, drive the plug out of the casting.
    8.  

  2.  

The hardened plug will break rather than remaining intact. It is not necessary to remove the plug whole; instead, remove loose pieces to allow use of Idle Mixture Adjusting tool J-29030, BT-7610B or equivalent.

  1. Using the tool J-29030, BT-7610B or equivalent, remove the idle mixture needle and spring from the throttle body.
  2.  

E2SE Reassembly

See Figures 49 through 56

THROTTLE BODY ASSEMBLY
  1. Holding the primary throttle lever wide-open, install the lower end of the pump rod in the throttle lever by aligning the raised portion on the rod with the slot in the lever.
  2.  
  3. If removed, install the idle mixture needle and spring using tool J-29030 or equivalent. Lightly seat the needle and then back out 4 turns as a preliminary idle mixture adjustment. Final idle mixture adjustment must be made on-vehicle.
  4.  



Click image to see an enlarged view

Fig. Fig. 49: Lockout lever



Click image to see an enlarged view

Fig. Fig. 50: Choke assembly

FLOAT BOWL ASSEMBLY
  1. Install a new throttle-to-bowl gasket over the 2 locating dowels on the bowl.
  2.  

If a new float bowl assembly is used, stamp or engrave the model number from the old float bowl on the new float bowl.

  1. Rotate the fast idle cam so the steps face the fast idle screw on the throttle lever, install the throttle body making certain the throttle body is properly located over the dowels on the float bowl; then install the throttle body-to-bowl screws and lockwashers tightening them evenly and securely.
  2.  
  3. Inspect the linkage to insure the lockout tang is located properly to engage the slot in the secondary lockout lever. Make sure that the linkage moves freely and does not bind.
  4.  
  5. Place the carburetor on suitable holding fixture.
  6.  
  7. Install the fuel inlet filter spring, the filter assembly, a new gasket and inlet nut, then tighten the nut to 18 ft. lbs. (24 Nm). When installing a service replacement filter, make sure the filter is the type that includes the check valve to meet the U.S. Motor Vehicle Safety Standards (MVSS). When properly installed, the hole (check valve end) in the filter faces toward the inlet nut.
  8.  

Tightening beyond the specified torque can damage the nylon gasket and cause a fuel leak.

  1. Install the choke housing on the throttle body, making sure the raised boss and locating lug on the rear of the housing fit into the recesses in the float bowl casting. Install the choke housing attaching screws and lockwashers, then tighten the screws evenly and securely.
  2.  
  3. Install the intermediate choke shaft assembly in the float bowl by pushing the shaft through from the throttle lever side.
  4.  
  5. With the intermediate choke lever in the UP (12 o'clock) position, install the coil lever inside the choke housing onto the flats on the intermediate shaft. The choke coil lever is properly aligned when the coil pick-up tang is in the UP position. Install the coil lever retaining screws into the end of the intermediate choke shaft and tighten securely.
  6.  
  7. Install the pump discharge check ball, the spring and a new plastic retainer in the float bowl. Tap lightly into place until the top of retainer is flush with the bowl casting surface.
  8.  
  9. Using a suitable prytool, install the float valve seat (with gasket) and the metering jet; tighten securely.
  10.  
  11. To make the adjustment easier, carefully bend the float arm upward at the notch in the arm before assembly.
  12.  
  13. Install the float valve onto the arm by sliding the float lever under the pull clip. The correct installation of the pull clip is to hook the clip over the edge of the float on the arm facing the float pontoon.
  14.  
  15. Install the hinge pin into the float arm with the end loop of the pin facing the pump well. Then, install the float assembly by aligning the valve in the seat and the float pin into locating channels in the float bowl.
  16.  
  17. To adjust the float level, perform the following procedures:
    1. Hold the float pin firmly in place and push down lightly on the arm at the outer end against the top of the float valve.
    2.  
    3. Using an adjustment "T'' scale, measure from the top of the float bowl casting surface (air horn gasket removed) to the top of the float at the toe.
    4.  
    5. Bend the float arm, as necessary, for proper adjustment by pushing on the pontoon.
    6.  
    7. Visually check the float alignment after adjustment.
    8.  

  18.  
  19. Install the plastic filler block over the float valve by pressing downward until properly seated (flush with the bowl casting surface).
  20.  
  21. Install the Throttle Position Sensor (TPS) return spring in the bottom of the well in the float bowl.
  22.  
  23. Install the Throttle Position Sensor (TPS) and the connector assembly in the float bowl by aligning the groove in the electrical connector with the "V'' in the float bowl casting, push down on the connector and sensor assembly so the connector wires and sensor are located below the bowl casting surface.
  24.  

Care must be taken when installing the throttle position sensor to assure that the electrical integrity is maintained. Make sure the wires between the connector and sensor assembly are not pinched or the insulation broken upon final assembly. Accidental electrical grounding of the TPS must be avoided.

  1. Install the air horn gasket on the float bowl, locating the gasket over the 2 dowel locating pins on the bowl.
  2.  
  3. Install the pump return spring and plunger in the pump well.
  4.  



Click image to see an enlarged view

Fig. Fig. 51: Fast idle cam linkage



Click image to see an enlarged view

Fig. Fig. 52: Float bowl assembly (note, please refer to the carburetor exploded view key list for explanations of the numbers)



Click image to see an enlarged view

Fig. Fig. 53: Installing the air horn to the float bowl (note, please refer to the carburetor exploded view key list for explanations of the numbers)

AIR HORN ASSEMBLY
  1. Install the new pump plunger stem seal and retainer in the air horn casting. Lightly stake the seal retainer in 3 places, choosing locations different from the original .
  2.  
  3. Install new Throttle Position Sensor (TPS) actuator plunger seal and retainer in the air horn casting. Lightly stake the seal retainer in 3 places, choosing locations different from the original .
  4.  
  5. Install the vent/screen assembly by installing the 2 small attaching screws; tighten securely.
  6.  
  7. Inspect the air valve shaft pin for lubrication, apply a liberal quantity of lithium base grease to the air valve shaft pin. Make sure to lubricate the pin surface contacted by the windup spring.
  8.  
  9. Install the fast idle cam rod in lower hole of the choke lever, aligning the squirt on the rod with the small slot in the lever.
  10.  
  11. Install the TPS plunger through the seal in the air horn until about 1 / 2 of the plunger extends above the surface of the air horn casting. Seal pressure should hold the plunger in place during the air horn installation on the float bowl.
  12.  

AIR HORN-TO-BOWL INSTALLATION
  1. Rotate the fast idle cam to the full UP position and tilt the air horn assembly to engage the lower end of the fast idle cam rod in the slot in the fast idle cam and install the pump rod end into hole in the pump lever; check the intermediate choke rod for position, then, holding down on the pump plunger assembly, carefully lower the air horn assembly onto the float bowl, guiding the pump plunger stem through the seal in the air horn casting. Do not force the air horn assembly onto the bowl but rather lightly lower it into place. Make sure the TPS actuator plunger engages the sensor plunger in the bowl by checking the plunger movement.
  2.  
  3. Install the air horn-to-bowl screws and lockwashers, tighten evenly and securely.
  4.  
  5. Install the new retainer clip through the hole in the end of the pump rod extending through the pump lever, making sure the clip securely locked in place.
  6.  
  7. Install the mixture control solenoid spacer and new rubber seal on the mixture control solenoid stem making sure the seal is up against the spacer. Then, using a 3 / 16 in. socket and light hammer, carefully drive a new retainer on the stem. Drive the retainer onto the stem only far enough to retain the rubber seal on the stem leaving a slight clearance between the retainer and seal to allow for seal expansion.
  8.  
  9. Prior to installing the mixture control solenoid, lightly coat the rubber seal on the end of the solenoid stem with a silicone grease or light engine oil. Using a new mounting gasket, install the mixture control solenoid on the air horn, carefully aligning the solenoid stem with the recess in bottom of the bowl. Use a slight twisting motion of the solenoid during installation to ensure the rubber seal on stem is guided into the recess in the bottom of the bowl. This will prevent distortion or damage to the rubber seal. Install the solenoid attaching screws and tighten securely.
  10.  
  11. Install the plastic bushing in the hole in the choke lever, making sure the small end of the bushing faces the retaining clip. With the inner coil lever and intermediate choke lever at the 12 o'clock position, install the intermediate choke rod in the bushing. Retain the rod with a new clip, pressing the clip securely in place with needle nose pliers. Make sure the clip has full contact on the rod is not seated tightly against the bushing. The rod-to-bushing clearance should be 0.030 in. (0.762mm).
  12.  
  13. Install the secondary vacuum break assembly. Rotate the assembly and insert the end ("T" pin) of the vacuum break link into the upper slot of the choke lever. Attach the bracket with countersunk screws and tighten the screws securely.
  14.  
  15. If the air valve rod has been removed from the primary side vacuum break plunger, install a plastic bushing in the hole in the primary side vacuum break plunger, making sure the small end of the bushing faces the retaining clip when installed. Then, insert the end of the air valve rod through the bushing. Retain with a new clip, pressing the clip into place using needle-nose pliers. Make sure the clip has full contact on the rod but is not seated tightly against the bushing. The rod-to-bushing clearance should be 0.030 in. (0.762mm).
  16.  
  17. Rotate the primary side vacuum break assembly (with the idle speed solenoid and bracket), then insert the end of the air valve rod into the slot of the air valve lever and the end ("T'' pin) of the vacuum break link into the lower slot of the choke lever. Connect the primary vacuum break hose on the throttle body and tube on the vacuum break unit. Position the bracket over the locating lug on the air horn and install the two counter sunk screws on the air horn with lockwashers onto the throttle body; tighten the screws securely.
  18.  
  19. Perform the choke coil lever adjustment procedure.
  20.  
  21. Install the choke cover and coil assembly in the choke housing, aligning the notch in the cover with the raised casting projection on the housing cover flange. Make sure the coil pickup tank engages the inside choke coil lever.
  22.  

Make sure the coil pick-up lever is located inside the coil tang when installing the choke cover and coil assembly.

The ground contact for the electric choke is provided by a metal plate located at the rear of the choke cover assembly. Do not install a choke cover gasket between the electrical choke assembly and the choke housing. A choke cover retainer kit is required to attach the choke cover-to-choke housing. Install the proper retainers and rivets contained in kit, using a blind rivet installation tool.



Click image to see an enlarged view

Fig. Fig. 54: Air horn tightening sequence



Click image to see an enlarged view

Fig. Fig. 55: Vacuum breaks and links (note: please refer to the carburetor exploded view key list for explanations of the numbers)



Click image to see an enlarged view

Fig. Fig. 56: Link to bushing clearance

E4ME/E4MC Disassembly

See Figures 57 through 61

IDLE SPEED CONTROL SOLENOID REMOVAL

Remove the attaching screws, then remove the Idle Speed Control (ISC) solenoid. The ISC should not be immersed in any carburetor cleaner. They must always be removed before complete carburetor overhaul, as carburetor cleaner will damage the internal components.

IDLE MIXTURE NEEDLE PLUG REMOVAL
  1. Use a hacksaw to make 2 parallel cuts in the throttle body, 1 on each side of the locator points near an idle mixture needle plug. The distance between the cuts will depend on the size of the punch to be used. Cuts should reach down to the steel plug, but should but extend more than 1 / 8 in. (3mm) beyond the locator points.
  2.  
  3. Place a flat punch at a point near the ends of the saw marks in the throttle body. Hold the punch at a 45 degree angle and drive it into the throttle body until the casting breaks away, exposing the hardened steel plug. The plug will break, rather than remain intact. Remove all the loose pieces.
  4.  
  5. Repeat the procedure for the other idle mixture needle plug.
  6.  

IDLE AIR BLEED VALVE REMOVAL
  1. Cover internal bowl vents and air inlets to the bleed valve with masking tape.
  2.  
  3. Carefully align a 7 / 64 in. (0.11mm) drill bit on rivet head. Drill only enough to remove head of each rivet holding the idle air bleed valve cover.
  4.  
  5. Use a suitably sized punch to drive out the remainder of the rivet from the castings. Repeat procedure with other rivet.
  6.  


CAUTION
For the next operation, safety glasses must be worn to protect your eyes from metal shavings.

  1. Lift off cover and remove any pieces of rivet still inside tower. Use compressed air to blow out any remaining chips.
  2.  
  3. Remove idle air bleed valve from the air horn.
  4.  
  5. Remove and discard O-ring seals from valve. New O-ring seals are required for reassembly. The idle air bleed valve is serviced as a complete assembly only.
  6.  

AIR HORN REMOVAL
  1. Remove upper choke lever from the end of choke shaft by removing the retaining screw. Rotate the lever to remove the choke rod from the slot on the lever.
  2.  
  3. Remove the choke rod from the lower lever inside the float bowl casting. Remove the rod by holding the lower lever outward with a small suitable tool and twisting the rod counterclockwise.
  4.  
  5. Remove secondary metering rods by removing the small screw in the top of the metering rod hanger. Lift upwards on the metering rod hanger until the secondary metering rods are completely out of the air horn. Metering rods may be disassembled from the hanger by rotating the ends out of the holes in the end of the hanger.
  6.  
  7. Remove the pump link retainer and remove the link from pump lever.
  8.  

Do not attempt to remove the lever, as damage to the air horn could result.

  1. Remove the front vacuum break hose from the tube on float bowl.
  2.  
  3. Remove the 11 air horn-to-bowl attaching screws; then remove the 2 countersunk attaching screws located next to the venturi. If used, remove the secondary air baffle deflector from beneath the 2 center air horn screws.
  4.  
  5. Remove air horn from float bowl by lifting it straight up. The air horn gasket should remain on the float bowl for removal later.
  6.  

When removing air horn from float bowl, use care to prevent damaging the mixture control solenoid connector, Throttle Position Sensor (TPS) adjustment lever and the small tubes protruding from the air horn. These tubes are permanently pressed into the air horn casting. Do not remove them. Do not place vacuum break assembly in carburetor cleaner, as damage to vacuum break will occur.

  1. Remove front vacuum break bracket attaching screws. The vacuum break assembly may now be removed from the air valve dashpot rod and the dashpot rod from the air valve lever.
  2.  
  3. Remove TPS plunger by pushing plunger down through seal in air horn.
  4.  
  5. Remove TPS seal and pump plunger stem seal by inverting air horn and using a small suitable tool to remove staking holding seal retainers in place. Remove and discard retainers and seals.
  6.  

Use care in removing the TPS plunger seal retainer and pump plunger stem seal retainer to prevent damage to air horn casting. New seals and retainers are required for reassembly.

  1. Invert air horn and use tool J-28696-4, BT-7967A, or equivalent, to remove rich mixture stop screw and spring.
  2.  
  3. Use a suitable punch to drive the lean mixture screw plug and rich mixture stop screw plug out of the air horn. Discard the plugs.
  4.  
  5. Further disassembly of the air horn is not required for cleaning purposes.
  6.  

The choke valve and choke valve screws, the air valves and air valve shaft should not be removed. However, if it is necessary to replace the air valve closing springs or center plastic eccentric cam, a repair kit is available. Instructions for assembly are included in the repair kit.

Click image to see an enlarged view

Fig. Fig. 57: Exploded view of the E4ME and E4MC carburetors



Click image to see an enlarged view

Fig. Fig. 58: Component key list for the E4ME and E4MC carburetors



Click image to see an enlarged view

Fig. Fig. 59: Removing the secondary metering rods



Click image to see an enlarged view

Fig. Fig. 60: Removing the pump lever roll pin

FLOAT BOWL DISASSEMBLY
  1. Remove solenoid metering rod plunger by lifting straight up.
  2.  
  3. Remove air horn gasket by lifting it from the dowel locating pins on float bowl. Discard gasket.
  4.  
  5. Remove pump plunger from pump well.
  6.  
  7. Remove staking holding Throttle Position Sensor (TPS) in bowl as follows:
    1. Lay a flat tool or metal piece across bowl casting to protect gasket sealing surface.
    2.  
    3. Use a small suitable tool to depress TPS lightly and hold against spring tension.
    4.  
    5. Observing safety precautions, pry upward with a small prybar, or other suitable tool, to remove bowl staking, making sure prying force is exerted against the metal piece and not against the bowl casting. Use care not to damage the TPS.
    6.  
    7. Push up from bottom on electrical connector and remove TPS and connector assembly from bowl. Use care in removing sensor and connector assembly to prevent damage to this critical electrical part.
    8.  
    9. Remove spring from bottom of TPS well in float bowl.
    10.  

  8.  
  9. Remove plastic bowl insert from float bowl.
  10.  
  11. Carefully lift each metering rod out of the guided metering jet, checking to be sure the return spring is removed with each metering rod.
  12.  

Use extreme care when handling these critical parts to avoid damage to the metering rod and spring.

  1. Remove the mixture control solenoid from the float bowl as follows:
    1. Remove screw attaching the solenoid connector to float bowl. Do not remove solenoid connector from float bowl until called for in text.
    2.  
    3. Use tool J-28696-10, BT-7928, or equivalent, to remove the lean mixture (solenoid) screw. Do not remove the plunger return spring or the connector and wires from the solenoid body. The mixture control solenoid, with plunger and connector, is only serviced as a complete assembly.
    4.  
    5. Remove the rubber gasket from top of solenoid connector and discard.
    6.  
    7. Remove the solenoid screw tension spring (next to float hanger pin).
    8.  

  2.  
  3. Remove float assembly and float needle by pulling up on retaining pin. Remove needle and seat and gasket using set remover tool J-22769, BT-3006M, or equivalent.
  4.  
  5. Remove the large mixture control solenoid tension spring from the boss on the bottom of float bowl located between the guided metering jets.
  6.  
  7. If necessary, remove the primary main metering jets using special tool J-28696-4, BT-7928, or equivalent.
  8.  

Use care when installing the tool to prevent damage to the metering rod guide. Also, no attempt should be made to remove the secondary metering jets (metering orifice plates). These jets are fixed and, if damaged, entire bowl replacement is required.

  1. Remove the pump discharge check ball retainer and turn bowl upside down, catching the discharge ball as it falls.
  2.  
  3. Remove the secondary air baffle, if replacement is required.
  4.  
  5. Remove the pump well fill slot baffle only if necessary.
  6.  



Click image to see an enlarged view

Fig. Fig. 61: Removing the solenoid-metering rod plunger

CHOKE DISASSEMBLY

The tamper-resistant choke cover is used to discourage unnecessary readjustment of the choke thermostatic cover and coil assembly. However, it is necessary to remove the cover and coil assembly for cleaning and overhaul.

  1. Support the float bowl and throttle body, as an assembly, on a suitable holding fixture such as tool J-9789-118, BT-30-15, or equivalent.
  2.  
  3. Carefully align a No. 21 drill (0.159 in./4mm) bit on the rivet head and drill only enough to remove rivet head. Drill the two remaining rivet heads, then use a drift and small hammer to drive the remainder of the rivets out of the choke housing.
  4.  

Use care in drilling to prevent damage to the choke cover or housing.

  1. Remove the retainers and choke cover assembly from the choke housing.
  2.  
  3. Remove the choke housing assembly from the float bowl by removing the retaining screw and washer inside the choke housing. The complete choke assembly can be removed from the float bowl by sliding it outward.
  4.  
  5. Remove the secondary throttle valve lock-out lever from float bowl.
  6.  
  7. Remove the lower choke lever from inside the float bowl cavity by inverting bowl.
  8.  
  9. To remove the intermediate choke shaft from the choke housing, remove the coil lever retaining screw from inside the choke housing.
  10.  
  11. Remove intermediate choke shaft from the choke housing by sliding it outward. The fast idle cam can now be removed from the intermediate choke shaft. Remove the cup seal from the float bowl cleaning purposes. Do not attempt to remove the insert.
  12.  
  13. Remove fuel inlet nut, gasket, check valve, filter assembly and spring. Discard check valve filter assembly and gasket.
  14.  
  15. Remove the 3 throttle body-to-bowl attaching screws and lockwashers, then remove the throttle body assembly.
  16.  

THROTTLE BODY DISASSEMBLY

Place throttle body assembly on a carburetor holding fixture to avoid damage to the throttle valves.

  1. Remove the pump rod from the throttle lever by rotating the rod until the tang on the rod aligns with the slot in the lever.
  2.  
  3. Use tool J-29030-B, BT-7610B, or equivalent, to remove the idle mixture needles for thorough throttle body cleaning.
  4.  
  5. Further disassembly of the throttle body is not required for cleaning purposes. The throttle valve screws are permanently staked in place and should not be removed. The throttle body is serviced as a complete assembly.
  6.  

E4MC/E4ME Reassembly

See Figures 62 through 68

  1. Install the lower end of the pump rod in the throttle lever by aligning the tang on the rod with the slot in the lever. The end of the rod should point outward toward the throttle lever.
  2.  
  3. Install the idle mixture needles and springs using tool J-29030-B, BT-07610B, or equivalent. Lightly seat each needle and then turn counterclockwise the number of specified turns. The final idle mixture adjustment is made on the vehicle.
  4.  
  5. If a new float bowl assembly is used, stamp or engrave the model number from the old float bowl onto the new float bowl. Install a new throttle body-to-bowl insulator gasket over the two locating dowels on the bowl.
  6.  
  7. Install the throttle body making certain it is properly located on the float bowl. Install the three throttle body-to-bowl screws and lockwashers, tighten them evenly and securely.
  8.  
  9. Place the carburetor on a proper holding fixture such as J-9789-118, BT-30-15 or equivalent.
  10.  
  11. Install the fuel inlet filter spring, a new check valve filter assembly, new gasket and inlet nut. Tighten nut to 18 ft. lbs. (24 Nm).
  12.  

When installing a service replacement filter, make sure the filter is the type that includes the check valve to meet government safety standards. New service replacement filters with check valves meet this requirement. When properly installed, the hole in the filter faces toward the inlet nut. Ribs on the closed end of the filter element prevent it from being installed incorrectly, unless forced. Tightening beyond the specified torque can damage the nylon gasket.

  1. Install a new cup seal into the insert on the side of the float bowl for the intermediate choke shaft. The lip on the cup seal faces outward.
  2.  
  3. Install the secondary throttle valve lock-out lever on the boss of the float bowl, with the recess hole in the lever facing inward.
  4.  
  5. Install the fast idle cam on the intermediate choke shaft (steps on cam face downward).
  6.  
  7. Carefully install the fast idle cam and the intermediate choke shaft assembly into the choke housing. Install the thermostatic coil lever onto the intermediate choke shaft. It is properly aligned when both inside and outside levers face toward the fuel inlet. Install the retaining screw into the end of the intermediate choke shaft.
  8.  
  9. Install the lower choke rod (inner) lever into the cavity in the float bowl.
  10.  
  11. Install the choke housing, sliding the intermediate choke shaft into the lower (inner) lever. Tool J-23417, BT-6911 or equivalent, can be used to hold the lower choke lever in the correct position while installing the choke housing. The intermediate choke shaft lever and the fast idle cam are in position when the tang on the lever is beneath the fast idle cam.
  12.  
  13. Install the choke housing retaining screws and washers. Check the linkage for freedom of movement. Do not install choke cover and coil assembly until the coil lever is adjusted.
  14.  
  15. If removed, install the air baffle in the secondary side of the float bowl with the notches toward the top. The top edge of the baffle must be flush with the bowl casting.
  16.  
  17. If removed, install the baffle inside of the pump well with the slot toward the bottom.
  18.  
  19. Install the pump discharge check ball and retainer screw in the passage next to the pump well.
  20.  
  21. If removed, carefully install the primary main metering jets using tool J-28696-4, BT-7928, or equivalent.
  22.  

Use care when installing jets to prevent damage to the metering rod guide.

  1. Install the large mixture control solenoid tension spring.
  2.  
  3. Install the needle and seat assembly with a new gasket, using seat installer J-22769, BT-3006M, or equivalent.
  4.  
  5. To make adjustment easier, carefully bend the float arm upwards before assembly.
  6.  
  7. Install the float needle onto the arm by sliding the float lever under needle pull clip. Proper installation of the needle pull clip is to hook the clip over the edge of the float arm.
  8.  
  9. Install the float hinge pin into the float arm with the end loop of the pin facing the pump well. Install the float assembly by aligning the needle in the seat and float hinge pin into the locating channels in the float bowl. Do not install the float needle pull clip into the holes in the float arm.
  10.  
  11. Perform a float level adjustment, as necessary.
  12.  
  13. Install the mixture control solenoid screw tension spring between raised bosses next to the float hanger pin.
  14.  
  15. Install the mixture control solenoid and connector assembly as follows:
    1. Install a new rubber gasket on top of the solenoid connector.
    2.  
    3. Install the solenoid carefully into the float chamber, aligning the pin on the end of the solenoid with the hole in the raised boss at the bottom of the bowl. Align the solenoid connector wires to fit in the slot in the bowl.
    4.  
    5. Install the lean mixture (solenoid) screw through the hole in the solenoid bracket and tension spring in the bowl.
    6.  
    7. Install mixture control solenoid gauging tool J-33815-1, BT-8253-A, or equivalent over the throttle side metering jet rod guide and temporarily install the solenoid plunger.
    8.  
    9. Holding the solenoid plunger against the solenoid stop, use tool J-28696-10, BT-7928, or equivalent, to turn the lean mixture (solenoid) screw slowly clockwise, until the solenoid plunger just contacts the gauging tool. The adjustment is correct when the solenoid plunger is contacting both the solenoid stop and the gauging tool.
    10.  
    11. Remove the solenoid plunger and gauging tool.
    12.  

  16.  
  17. Install the connector attaching screw, do not overtighten.
  18.  
  19. Install the Throttle Position Sensor (TPS) return spring in the bottom of well in the float bowl.
  20.  
  21. Install the TPS and connector assembly in the float bowl. Align the groove in the electrical connector with the slot in the float bowl casting. Push down on the connector and sensor assembly so that the connector and wires are below the bowl casting surface.
  22.  
  23. Install the plastic bowl insert over the float valve, pressing downward until properly seated (flush with bowl casting surface).
  24.  
  25. Slide the metering rod return spring over the metering rod tip until the small end of the spring stops against the shoulder on the rod. Carefully install the metering rod and spring assembly into the guided metering jet, until the large end of the spring seats on the recess of the jet guide.
  26.  

Do not force the metering rod down into the jet. Use extreme care when handling these delicate parts to avoid damage to rod and spring. If replacement metering rods, springs and jets are installed, they must be installed in matched sets.

  1. Install the pump return spring and plunger assembly into the pump well.
  2.  
  3. While holding down on the pump plunger assembly, install the air horn gasket by aligning the pump plunger stem with the hole in gasket and aligning holes in gasket over TPS plunger, solenoid plunger return spring metering rods, solenoid attaching screw and electrical connector. Position the gasket over the 2 dowel locating pins on the float bowl.
  4.  
  5. While holding down on air horn gasket and pump plunger assembly, install the solenoid-metering rod plunger in the solenoid. Align the slot on the end of the plunger with the solenoid attaching screw. Be sure the plunger arms engage the top of each metering rod.
  6.  
  7. If a replacement mixture control solenoid is installed, the solenoid and plunger MUST be installed as a matched set.
  8.  



Click image to see an enlarged view

Fig. Fig. 62: Choke assembly



Click image to see an enlarged view

Fig. Fig. 63: Installing the lower choke lever



Click image to see an enlarged view

Fig. Fig. 64: Float needle pull clip location

Air Horn Assembly
  1. If removed, install the Throttle Position Sensor (TPS) adjustment screw in the air horn using tool J-28696-10, BT-7967A, or equivalent. Final adjustment of the TPS is made on the vehicle.
  2.  
  3. Inspect the air valve shaft pin for lubrication. Apply a liberal quantity of lithium base grease to the pin, especially in the area contacted by the spring.
  4.  
  5. Install the new pump plunger and TPS plunger seals and retainers in air horn casting. The lip on the seal faces outward, away from the air horn mounting surface. Lightly stake the seal retainer in 3 places, choosing locations different from the original stakings.
  6.  
  7. Install the rich mixture stop screw and spring. Use tool J-2869-4, BT-7967A, or equivalent, to bottom the stop screw lightly, then back out 1 / 4 turn. Final adjustment procedure must be performed later.
  8.  
  9. Install the TPS actuator plunger in the seal.
  10.  
  11. Carefully lower the air horn assembly onto the float bowl while positioning the TPS adjustment lever over the TPS and guiding the pump plunger stem through the seal in the air horn casting. To ease installation, insert a thin suitable tool between the air horn gasket and float bowl to raise the TPS adjustment lever, positioning it over the TPS.
  12.  
  13. Make sure that the bleed tubes and accelerating well tubes are positioned properly through the holes in the air horn gasket. Do not force the air horn assembly onto the bowl, but lower it lightly into place over the two dowel locating pins.
  14.  
  15. Install the two long air horn screws and lockwashers, nine short screws and lockwashers and the two countersunk screws located next to the carburetor venturi area. Install the secondary air baffle beneath the No. 3 and 4 screws. Tighten all screws evenly and securely.
  16.  
  17. Install the air valve rod into the slot in the lever on the end of the air valve shaft. Install the other end of the rod in the hole in the front vacuum break plunger. Install the front vacuum break and bracket assembly on the air horn. Tighten the screws securely. Connect the pump link to the pump lever and install the retainer.
  18.  

Use care when installing the roll pin to prevent damage to the pump lever bearing surface and casting bosses.

  1. Install the two secondary metering rods into the secondary metering rod holder (upper end of rods point toward each other). Install the secondary metering rod holder, with rods, onto air valve cam follower. Install the retaining screw and tighten securely. Work air valves up and down several times to make sure they remove freely in both directions.
  2.  
  3. Connect the choke rod to the lower choke lever inside the bowl cavity. Install the choke rod to the upper choke lever. Position the lever on the end of the choke shaft. Install the attaching screw and tighten securely. When properly installed, the number on the lever will face outward.
  4.  
  5. Adjust the rich mixture stop screw:
    1. Insert external float gauging tool J-34935-1, BT-8420A, or equivalent, in the vertical D-shaped vent hole in the air horn casting (next to the idle air bleed valve) and allow it to float freely.
    2.  
    3. Read (at eye level) the mark on the gauge, in inches, that lines up with the tip of the air horn casting.
    4.  
    5. Lightly press down on the gauge, reading and recording the mark on the gauge that lines up with the top of the air horn casting.
    6.  
    7. Subtract the gauge UP dimension from the gauge DOWN dimension and record the difference in inches. This difference is the total solenoid plunger travel.
    8.  
    9. Insert tool J-28696-10, BT-7928, or equivalent, in the access hole in the air horn and adjust the rich mixture stop screw to obtain 1 / 8 in. (3mm) total solenoid plunger travel.
    10.  

  6.  
  7. With the solenoid plunger travel correctly set, install the plugs supplied in the service kit into the air horn to retain the setting and prevent fuel vapor loss.
  8.  
  9. Install the idle air bleed valve as follows:
    1. Lightly coat two new O-ring seals with automatic transmission fluid, to aid in their installation. The thick seal goes in the upper groove and the thin seal goes in the lower groove.
    2.  
    3. Install the idle air bleed valve in the air horn, making sure that there is proper thread engagement.
    4.  
    5. Insert idle air bleed valve gauging tool J-33815-2, BT-8353B, or equivalent, in the throttle side D-shaped vent hole of the air horn casting. The upper end of the tool should be positioned over the open cavity next to the idle air bleed valve.
    6.  
    7. Hold the gauging tool down lightly so that the solenoid plunger is against the solenoid stop, then adjust the idle air bleed valve so that the gauging tool will pivot over and just contact the top of the valve.
    8.  
    9. Remove the gauging tool.
    10.  
    11. The final adjustment of the idle air bleed valve is made on the vehicle to obtain idle mixture control.
    12.  

  10.  
  11. Perform the air valve spring adjustment and choke coil lever adjustment.
  12.  
  13. Install the cover and coil assembly in the choke housing, as follows:
    1. Place the cam follower on the highest step of the fast idle cam.
    2.  
    3. Install the thermostatic cover and coil assembly in the choke housing, making sure the coil tang engages the inside coil pickup lever. Ground contact for the electric choke is provided by a metal plate located at the rear of the choke cover assembly. Do not install a choke cover gasket between the electric choke assembly and the choke housing.
    4.  
    5. A choke cover retainer kit is required to attach the choke cover to the choke housing. Follow the instructions found in the kit, then install the proper retainer and rivets using a suitable blind rivet tool.
    6.  
    7. It may be necessary to use an adapter (tube) if the installing tool interferes with the electrical connector tower on the choke cover.
    8.  

  14.  
  15. Install the hose on the front vacuum brake and on the tube on the float bowl.
  16.  
  17. Position the idle speed solenoid and bracket assembly on the float bowl, retaining it with the countersunk screws.
  18.  
  19. Perform the choke rod-fast idle cam adjustment, primary (front) vacuum break adjustment, air valve rod adjustment-front, unloader adjustment and the secondary lockout adjustment.
  20.  
  21. Reinstall the carburetor on the vehicle with a new flange gasket.
  22.  



Click image to see an enlarged view

Fig. Fig. 65: Lubrication of the air valve shaft pin



Click image to see an enlarged view

Fig. Fig. 66: Installing the air bleed valve O-rings



Click image to see an enlarged view

Fig. Fig. 67: Raising the TPS lever when installing the air horn



Click image to see an enlarged view

Fig. Fig. 68: Air horn screw tightening sequence

 
label.common.footer.alt.autozoneLogo