Jeep Wagoneer/Commando/Cherokee 1984-1998

Rochester 2SE/E2SE Carburetor

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The Rochester 2SE and E2SE carburetors were used on 2.8L engines. The carburetor part number is stamped vertically on the float bowl in the float. Refer to this part number when servicing the carburetor.

Make all adjustments with the engine at normal operating temperature, choke plate fully opened, air cleaner removed, thermac vacuum source plugged and A/C off (except if needed for a certain adjustment). Set the idle speeds only when the emission control system is in closed loop mode.

ADJUSTMENTS



Float Level

See Figures 1 and 2

Special tools are needed for this procedure.

  1. Run the engine to normal operating temperature.
  2.  
  3. Remove the vent stack screws and the vent stack.
  4.  
  5. Remove the air horn screw adjacent to the vent stack.
  6.  
  7. With the engine idling and the choke fully opened, carefully insert float gauge J-9789-136 or its equivalent for E2SE carburetors, or J-9789-138 or its equivalent for 2SE carburetors, into the air horn screw hole and vent hole.
  8.  
  9. Allow the gauge to rest freely on the float. Do not press down on the float!
  10.  
  11. With the gauge at eye level, observe the mark that aligns with the top of the casting at the vent hole. The float level should be within 0.06 in. (1.5mm) of the specification listed in the chart. If not, remove the air horn and adjust as follows:
    1. Hold the retainer pin firmly in place and push the float down, lightly, against the inlet needle.
    2.  
    3. Using an adjustable T-scale, at a point 3 / 16 in. (4.8mm) from the end of the float, at the toe, measure the distance from the float bowl top surface (gasket removed) to the top of the float at the toe. If the distance isn't as specified in the Chart, remove the float and bend the float arm as necessary.

      Click image to see an enlarged view

      Fig. Fig. 1: Float adjustment on the E2SE/2SE carburetor



      Click image to see an enlarged view

      Fig. Fig. 2: Measuring float clearance on the E2SE/2SE carburetor

    4.  

  12.  

Fast Idle Speed

See Figure 3

  1. Place the fast idle screw on the high step of the fast idle cam.
  2.  
  3. Disconnect and plug the EGR valve hose and the canister purge line at the canister.
  4.  
  5. Set the parking brake firmly and start the engine. Place the transmission in Neutral (manual) or Park (automatic).
  6.  
  7. Turn the fast idle screw in or out to obtain the specified fast idle speed. Refer to the underhood emission sticker for fast idle speed specifications.
  8.  
  9. Once all adjustments are complete, reconnect the EGR valve hose and the canister purge line at the canister.
  10.  



Click image to see an enlarged view

Fig. Fig. 3: Rochester 2SE adjustment points

Electric Choke Test
  1. Check voltage at the choke heater connection with the engine running. If voltage is 12-15 volts, replace the electric choke unit.
  2.  
  3. If the voltage is low or zero, check all wires and connections.
  4.  
  5. If Steps 1 and 2 pass the test properly, check and see if the connection on the oil pressure switch is faulty, the temperature pressure warning light will be off with the key in the ON position and the engine not running. Repair wires as required.
  6.  
  7. If the choke is still inoperative, replace the oil pressure switch.
  8.  

Choke Coil Lever Adjustment

See Figures 4 and 5

  1. Remove air cleaner and disconnect the choke electrical connector.
  2.  
  3. Align a 5 / 32 in. (4mm) drill on the retainer rivet head and drill only enough to remove rivet head. After removing rivet heads and retainers, use a drift and small hammer to drive the remainder of the rivet from the choke housing. Use care in drilling to prevent damage to the choke cover or housing. Remove the three rivets and choke cover assembly from choke housing.
  4.  
  5. Remove choke coil from housing.
  6.  

A choke stat cover retainer kit is required for reassembly.

  1. Place the fast idle screw on the high step of the dam.
  2.  
  3. Close the choke by pushing in on the intermediate choke lever. On front wheel drive models, the intermediate choke lever is behind the choke vacuum diaphragm.
  4.  
  5. Insert a drill or gauge of the specified size into the hole in the choke housing. The choke lever in the housing should be up against the side of the gauge.
  6.  
  7. If the lever does not just touch the gauge, bend the intermediate choke rod to adjust.
  8.  



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Fig. Fig. 4: Choke coil cap rivet locations (A)



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Fig. Fig. 5: Choke coil lever adjustment

To install:
  1. Install the choke cover and coil assembly in choke housing as follows:
    1. Install the choke cover and coil assembly in the choke housing, aligning notch in cover with raised casting projection on housing cover flange. Make sure coil pickup tank engages the inside choke coil lever.
    2.  
    3. A choke cover retainer kit is required to attach the choke cover to the choke housing. Install a suitable blind rivet installing tool.
    4.  

  2.  
  3. Engage choke electrical connector.
  4.  
  5. Start engine, check operation of choke and then install the air cleaner.
  6.  

Electric Choke Setting

This procedure is only for those carburetors with choke covers retained by screws. Riveted choke covers are preset and non-adjustable.

  1. Loosen the three retaining screws.
  2.  
  3. Place the fast idle screw on the high step of the cam.
  4.  
  5. Rotate the choke cover to align the cover mark with the specified housing mark.
  6.  

The specification "index'' which appears in the specification table refers to the mark between "1 notch lean'' and "1 notch rich''.

Secondary Lockout Adjustment
  1. Pull the choke wide open by pushing out on the intermediate choke lever.
  2.  
  3. Open the throttle until the end of the secondary actuating lever is opposite the toe of the lockout lever.
  4.  
  5. Gauge clearance between the lockout lever and secondary lever should be as specified.
  6.  
  7. To adjust, bend the lockout lever where it contacts the fast idle cam.
  8.  

Secondary Vacuum Break TVS Test

The secondary vacuum break Thermal Vacuum Switch (TVS), located in the air cleaner, improves cold starting and cold driveability by sensing carburetor air inlet temperature to control the carburetor secondary vacuum break.

  1. With engine at normal operating temperature, the Thermal Vacuum Switch (TVS) must be open (air cleaner cover on).
  2.  
  3. Apply either engine or auxiliary vacuum to the TVS inlet port and check for vacuum at the outlet port (outlet port connects to secondary vacuum break).
  4.  
  5. If there is no vacuum, check air cleaner assembly for leaks, thermostatic air cleaner vacuum hoses and/or replace the TVS. Replace the TVS as follows:
    1. Remove air cleaner cover and element.
    2.  
    3. Disconnect vacuum hoses.
    4.  
    5. Remove clip from TVS and remove TVS.
    6.  
    7. Install new TVS and replace clip.
    8.  
    9. Reconnect vacuum hoses (refer to Vehicle Emission Control Information Label).
    10.  
    11. Install air cleaner cover and element.
    12.  

  6.  

Idle Stop Solenoid Test

The solenoid should be checked to assure that the solenoid plunger extends when the solenoid is energized. an inoperative solenoid could cause stalling or a rough idle when hot, and should be replaced as necessary.

  1. Turn the ignition ON , but do not start engine. Position transmission lever in Drive (A/T) or Neutral (M/T). On vehicles equipped with air conditioning, A/C switch must be on.
  2.  
  3. Open and close throttle. The solenoid plunger should retract from throttle lever. Disconnect the wire at the solenoid, the solenoid plunger should retract from the throttle lever.
  4.  
  5. Connect solenoid wire and the plunger should move out and contact the throttle lever. the solenoid may not be strong enough to open the throttle, but the plunger should move.
  6.  
  7. If the plunger does not move in and out as the wire is disconnected and connected, check the voltage feed wire:
    1. If voltage is 12-15 volts, replace the solenoid.
    2.  
    3. If voltage is low or zero, locate the cause of the open circuit in the solenoid feed wire and repair.
    4.  

  8.  
  9. If necessary to replace the idle stop, proceed as follows.
    1. Remove carburetor air cleaner.
    2.  
    3. Disengage electrical connector at the solenoid.
    4.  
    5. Unfasten the large retaining nut, tabbed lock washer and remove the solenoid.
    6.  
    7. Install the solenoid and retaining nut, bending the lock tabs against nut flats.
    8.  
    9. Engage electrical connector.
    10.  
    11. Install air cleaner and adjust idle speed as necessary.
    12.  

  10.  

Carburetor Pre-Set Procedure

See Figures 6 and 7

  1. Remove the carburetor from the engine following normal service procedures to gain access to the plug covering the idle mixture needle.
  2.  
  3. To remove the plug, make two parallel cuts in the throttle body, one on each side of the plug, with a hacksaw. There is a locator point marking the casting at the plug. The cuts should extend down to the steel plug, but should not extend more than 1 / 8 in. (3mm) beyond the locator point.
  4.  
  5. Place a flat punch at a point near the ends of the saw cuts the throttle body. Hold the punch at a 45° angle and drive it into the throttle body until the casting breaks away and exposes the steel plug. Hold a center punch in the vertical position and drive it into the plug, then hold the punch at a 45° angle and drive the plug out of the housing. The hardened steel plug will shatter rather than remain intact. It is not necessary to remove the plug completely; instead, remove the loose pieces, then turn the idle mixture needle in until lightly seated and back out 4 turns.
  6.  
  7. If the plug in air horn covering the idle air has been removed replace air horn. If plug is still in place, do not remove plug.
  8.  



Click image to see an enlarged view

Fig. Fig. 6: Removing the idle mixture screw cover on the 2SE/E2SE carburetor

  1. Remove vent stack screen assembly to gain access to lean mixture screw. (Be sure to reinstall vent stack screen assembly after adjustment).
  2.  
  3. Using tool J-28696-10 BT 7928 or equivalent, turn lean mixture screw in until lightly bottomed and back out 2 1 / 2 turns.
  4.  
  5. Reinstall the carburetor on the engine and perform the following:
    1. Do not install air cleaner and gasket.
    2.  
    3. Disconnect the bowl vent line at carburetor.
    4.  
    5. Disconnect the EGR valve hose and canister purge hose at the carburetor and cap the carburetor ports.
    6.  
    7. Refer to Vehicle Emission Control Information Label and observe hose from sensor and secondary vacuum break TVS. Disconnect hose at temperature sensor on air cleaner and plug open hose.
    8.  
    9. Connect the positive lead of a dwell meter to the mixture control solenoid test lead (green connector). Connect the other meter lead to ground. Set dwell meter to 6 cylinder position. Connect a tachometer to distributor lead (brown connector). Tachometer should be connected to the distributor side of the tach filter if vehicle is equipped with a tachometer.
    10.  
    11. Block the drive wheels.
    12.  
    13. Place the transmission in Park (automatic transmission) or Neutral (manual transmission) and set the parking brake.
    14.  

  6.  



Click image to see an enlarged view

Fig. Fig. 7: Mixture control solenoid (6) removal/installation

Mixture Adjustment

See Figure 8

  1. Perform carburetor pre-set procedure.
  2.  
  3. Run engine on high step of fast idle cam until engine cooling fan starts to cycle (at least three minutes and until in closed loop).
  4.  
  5. Run the engine at 3000 rpm and adjust the lean mixture screw slowly in small increments allowing time for the dwell to stabilize after turning the screw to obtain an average dwell of 35°.
  6.  
  7. If dwell is too low, back screw out, if too high, turn it in.
  8.  
  9. If unable to adjust to specifications, inspect main metering circuit for leaks, restrictions, etc.
  10.  



Click image to see an enlarged view

Fig. Fig. 8: Adjust the idle mixture with tool J-29030-B or its equivalent

  1. The dwell reading of the M/C solenoid is used to determine calibration and is sensitive to changes in fuel mixture caused by heat, air leaks, etc. While idling, it is normal for the dwell to increase and decrease fairly constantly over a relatively narrow range, such as 5°. However, it may occasionally vary be as much as 10-15° momentarily due to temporary mixture changes.
  2.  
  3. The dwell reading specified is the average of the most consistent variation. The engine must be allowed a few moments to stabilize at idle or 3000 rpm as applicable before taking a dwell reading. Return to idle.
  4.  
  5. Adjust the idle mixture screw to obtain an average dwell of 25° with cooling fan in off cycle.
  6.  
  7. If reading is too low, back screw out. If too high, turn it in. Allow time for reading to stabilize after each adjustment. Adjustment is very sensitive. Make final check with adjusting tool removed.
  8.  
  9. If unable to adjust to specifications, inspect idle system for leaks, restrictions, etc.
  10.  
  11. Disconnect mixture control solenoid when cooling fan is in off cycle and check for an rpm change of at least 50 rpm. If rpm does not change enough, inspect idle air bleed circuit for restrictions, leaks, etc.
  12.  
  13. Run engine at 3000 rpm for a few moments and note dwell reading. Dwell should be varying with an average reading of 35°. If not at 35° average dwell, reset the lean mixture screw as per Step 3. Then reset the idle mixture screw to obtain 25° dwell as per Step 5.
  14.  
  15. If at 35° average dwell, reconnect the systems disconnected earlier (purge and vent hoses, EGR valve, etc.), reinstall vent screen and set idle speed to specifications.
  16.  

Removal & Installation



Always replace all internal gaskets that are removed. Base gasket should be inspected and replaced only if damaged. 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 the engine without draining fuel from bowl. Contents of the fuel bowl may then be examined for contamination as the carburetor is disassembled. Be sure to check the fuel filter.

  1. Remove the air cleaner and gasket.
  2.  
  3. Disconnect the fuel pipe and vacuum lines.
  4.  
  5. Disengage the electrical connectors.
  6.  
  7. Disconnect the accelerator linkage.
  8.  
  9. If equipped with automatic transmission, disconnect the downshift cable.
  10.  
  11. If equipped with cruise control, disconnect the linkage.
  12.  
  13. Remove the carburetor attaching bolts.
  14.  
  15. Remove the carburetor and EFE heater/insulator (if used).
  16.  
  17. Fill the carburetor bowl before installing carburetor. A small supply of fuel will enable the carburetor to be filled and the operation of the float and inlet needle and seat to be checked.
  18.  
  19. Operate throttle lever several times and check discharge from pump jets before installing carburetor.
  20.  

To install:
  1. Inspect EFE heater/insulator for damage. Be certain throttle body and EFE heater/insulator surfaces are clean.
  2.  
  3. Install EFE heater/insulator.
  4.  
  5. Install the carburetor and tighten the nuts alternately to the correct torque.
  6.  
  7. Connect the downshift cable as required.
  8.  
  9. Connect the cruise control cable as required.
  10.  
  11. Connect the accelerator linkage.
  12.  
  13. Engage the electrical connections.
  14.  
  15. Connect the fuel pipes and vacuum hoses.
  16.  
  17. Check the base (slow) and fast idle.
  18.  
  19. Install the air cleaner.
  20.  

 
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