Jeep CJ/Scrambler 1971-1986 Repair Guide

Carburetor

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5, 6, 7 and 8

Carter BBD
  1. Remove the air cleaner.
  2.  
  3. Disconnect the fuel and vacuum lines. It might be a good idea to tag them to avoid confusion when the time comes to put them back.
  4.  
  5. Disconnect the choke rod.
  6.  
  7. Disconnect the accelerator linkage.
  8.  
  9. Disconnect the automatic transmission linkage.
  10.  
  11. Unbolt and remove the carburetor.
  12.  
  13. Remove the base gasket.
  14.  
  15. Before installation, make sure that the carburetor and manifold sealing surfaces are clean.
  16.  
  17. Install a new carburetor base gasket.
  18.  
  19. Install the carburetor and start the fuel and vacuum lines.
  20.  
  21. Bolt down the carburetor evenly, tightening the bolts in a criss-cross pattern to 7 ft. lbs. (9 Nm), then to 14 ft. lbs. (19 Nm).
  22.  
  23. Tighten the fuel and vacuum lines.
  24.  
  25. Connect the accelerator and automatic transmission linkage. If the transmission linkage was disturbed, it will have to be adjusted.
  26.  
  27. Connect the choke rod.
  28.  
  29. Install the air cleaner. Adjust the idle speed and mixture.
  30.  

Rochester 2SE/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. Fill carburetor bowl before installing carburetor. A small supply of no-lead fuel will enable the carburetor to be filled and the operation of the float and inlet needle and seat to be checked. Operate throttle lever several times and check discharge from pump jets before installing carburetor.
  18.  
  19. Inspect EFE heater/insulator for damage. Be certain throttle body and EFE heater/insulator surfaces are clean.
  20.  
  21. Install EFE heater; insulator.
  22.  
  23. Install carburetor and tighten nuts alternately to the correct torque.
  24.  
  25. Connect downshift cable as required.
  26.  
  27. Connect cruise control cable as required.
  28.  
  29. Connect accelerator linkage.
  30.  
  31. Connect electrical connections.
  32.  
  33. Connect fuel pipe sand vacuum hoses.
  34.  
  35. Check base (slow) and fast idle.
  36.  
  37. Install air cleaner.
  38.  



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Fig. Fig. 1: Disconnect the throttle linkage at the carburetor



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Fig. Fig. 2: Pull the cable through the bracket



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Fig. Fig. 3: Disconnect the throttle return spring



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Fig. Fig. 4: Disconnect the choke linkage from the carburetor



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Fig. Fig. 5: Remove the carburetor mounting bolts



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Fig. Fig. 6: Lift the carburetor from the intake manifold



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Fig. Fig. 7: Remove the carburetor base plate



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Fig. Fig. 8: Remove the carburetor base gasket

Carter YF/YFA
  1. Remove the air cleaner.
  2.  
  3. Tag and disconnect all hoses leading to the carburetor.
  4.  
  5. Disconnect the control shaft from the throttle lever.
  6.  
  7. Disconnect the in-line fuel filter, pullback spring and all electrical connectors.
  8.  
  9. Remove the carburetor mounting nuts and lift off the carburetor.
  10.  
  11. Remove the carburetor mounting gasket from the spacer.
  12.  
  13. Clean all gasket mating surfaces on the spacer and carburetor.
  14.  
  15. Install a new gasket on the spacer, then install the carburetor and secure it with the mounting nuts.
  16.  
  17. Reconnect all vacuum hoses, fuel lines and electrical connectors. Connect the control shaft and pullback spring.
  18.  
  19. Install the air cleaner and adjust the curb and fast idle speed as previously described.
  20.  

Rochester 2G/2GV
  1. Remove the air cleaner.
  2.  
  3. Disconnect:
    1. Accelerator linkage.
    2.  
    3. Vacuum hoses.
    4.  
    5. Return spring.
    6.  
    7. PCV hose.
    8.  
    9. Fuel line.
    10.  

  4.  
  5. Remove the carburetor holddown nuts.
  6.  
  7. Remove the carburetor and mounting gasket.
  8.  
  9. Clean all gasket surfaces thoroughly.
  10.  
  11. Installation is the reverse of removal. Always use new gaskets. Tighten the nuts in a criss-cross pattern.
  12.  

Autolite/Motorcraft 2100/2150
  1. Remove the air cleaner.
  2.  
  3. Disconnect:
    1. Accelerator cable.
    2.  
    3. Vacuum hoses.
    4.  
    5. Pullback spring.
    6.  
    7. Choke clean air tube.
    8.  
    9. Solenoid wire.
    10.  
    11. PCV hose.
    12.  
    13. Fuel filter.
    14.  
    15. Choke heat tube.
    16.  

  4.  
  5. Remove the carburetor holddown nuts.
  6.  
  7. Remove the carburetor and mounting gasket. If an EGR spacer is used, remove this also and its gasket.
  8.  
  9. Clean all gasket surfaces thoroughly.
  10.  
  11. Installation is the reverse of removal. Always use new gaskets. Tighten the nuts in a criss-cross pattern.
  12.  

OVERHAUL



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. Keep all similar and look-alike parts segregated during disassembly and cleaning to avoid accidental interchange during assembly. Make a note of all jet sizes.

When the carburetor is disassemble, wash all parts (except diaphragms, electric choke units, 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 not 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. If wear is found, replace the complete assembly.
  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.

  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 if necessary. If the valve is satisfactory, wash the valve again to remove breath moisture.
  4.  
  5. Check the bowl cover for warped surfaces with a straightedge.
  6.  
  7. Closely inspect the valves and seats for wear and damage, replacing as necessary.
  8.  
  9. After the carburetor is assembled, check the choke valve for freedom of operation.
  10.  

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

Carburetor manufacturers supply overhaul kits of three basic types: minor repair, major repair, and gasket kits. Basically, they contain the following:



Minor Repair Kits
 
All gaskets
 
Float needle valve
 
Volume control screw
 
All diaphragms
 
Spring for the pump diaphragm
 



Major Repair Kits
 
All jets and gaskets
 
All diaphragms
 
Float needle valve
 
Volume control screw
 
Pump ball valve
 
Main jet carrier
 
Float
 
Complete intermediate rod
 
Intermediate pump lever
 
Complete injector tube
 
Some cover holddown screws and washers
 



Gasket Kits
 
All gaskets
 

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 adjust the float level when reassembling.

Carter BBD

See Figures 9 and 10

  1. Place carburetor on a repair stand to protect throttle valves from damage and to provide a stable base for working.
  2.  
  3. Remove retaining clip from accelerator pump arm link and remove line. Remove the stepper motor.
  4.  
  5. Remove step-up piston cover plate and gasket from top of air horn.
  6.  
  7. Remove the screws and locks from the accelerator pump arm and the vacuum piston rod lifter. Then slide the pump lever out to the air horn. The vacuum piston and step-up rods can now be lifted straight up and out of the air horn as an assembly.
  8.  
  9. Remove vacuum hose from between carburetor main body and choke vacuum diaphragm at main body tap.
  10.  
  11. Remove choke diaphragm, linkage and bracket assembly and place to one side to be cleaned as a separate item.
  12.  
  13. Remove retaining clip from fast idle cam link and remove link from choke shaft lever.
  14.  
  15. Remove fast idle cam retaining screw and remove fast idle cam and linkage.
  16.  
  17. Remove air horn retaining screws and lift air horn straight up and away from main body. Discard gasket.
  18.  
  19. Invert the air horn and compress accelerator pump drive spring and remove "S'' link from pump shaft. Pump assembly can now be removed.
  20.  
  21. Remove fuel inlet needle valve, seat and gasket from main body.
  22.  
  23. Lift out float fulcrum pin retainer and baffle. Then lift out floats and fulcrum pin.
  24.  
  25. Remove main metering jets.
  26.  
  27. Remove venturi cluster screws, then lift venturi cluster and gaskets up and away from main body. Discard gaskets. Do not remove the idle orifice tubes or main vent tubes from the cluster. They can be cleaned in a solvent and dried with compressed air.
  28.  
  29. Invert carburetor and drop out accelerator pump discharge and intake check balls.
  30.  
  31. Remove idle mixture screws from throttle body, after lightly bottoming and noting the number of turns. Record the turns in for reference when installing the mixture screws.
  32.  
  33. Remove screws that attach throttle body to main body. Separate bodies.
  34.  
  35. Test freeness of choke mechanism in air horn. The choke shaft must float free to operate correctly. If choke shaft sticks, or appears to be gummed from deposits in air horn, a thorough cleaning will be required.
  36.  
  37. The carburetor now has been disassembled into three main units: the air horn, main body, and throttle body. Components are disassembled as far as necessary for cleaning and inspection.
  38.  

THROTTLE BODY

Check throttle shaft for excessive wear in throttle body. If wear is extreme, it is recommended that throttle body assembly be replaced rather than installing a new shaft in old body. Install idle mixture screws in body. The tapered portion must be straight and smooth. If tapered portion is grooved or ridged, a new idle mixture screw should be installed to insure having correct idle mixture control.

MAIN BODY
  1. Invert main body and place insulator in position, then place throttle body on main body and align. Install screws and tighten securely.
  2.  
  3. Install accelerator pump discharge check ball ( 5 / 32 inch diameter) in discharge passage. Drop accelerator pump intake check ball ( 3 / 16 inch diameter) into bottom of the pump cylinder.
  4.  
  5. To check the accelerator pump system; fuel inlet and discharge check balls, proceed as follows:
  6.  
  7. Pour clean gasoline into carburetor bowl, approximately 1 / 2 inch deep. Remove pump plunger from container of mineral spirits and slide down into pump cylinder. Raise plunger and press lightly on plunger shaft to expel air from pump passage.
  8.  
  9. Using a small clean brass rod, hold discharge check ball down firmly on its seat. Again raise plunger and press downward. No fuel should be emitted form either intake or discharge passage. If any fuel does emit from either passage, it indicates the presence of dirt or a damaged check ball or seat. Clean passage again and repeat test. If leakage is still evident, stake check ball seats (place a piece of drill rod on top of check ball and lightly tap drill rod with a hammer to form a new seat), remove and discard old balls, and install new check balls. The fuel inlet check ball is located at bottom of the plunger well. Remove fuel from bowl.
  10.  
  11. Install discharge check ball. Install new gaskets on venturi cluster, then install in position in main body. Install cluster screws and tighten securely.
  12.  
  13. Install main metering jets.
  14.  



Click image to see an enlarged view

Fig. Fig. 9: Exploded view of the Carter BBD carburetor used on the 6-258 engine through 1983



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Fig. Fig. 10: Exploded view of the Carter BBD carburetor used on the 6-258 engine 1984-86

FLOAT

The carburetors are equipped with a synthetic rubber tipped fuel inlet needle. The needle tip is viton, which is not affected by gasoline and is stable over a wide range of temperatures. The tip is flexible enough to make a good seal on the needle seat, and to give increased resistance to flooding.

The use of the synthetic rubber tipped inlet needle requires that care be used in adjusting the float setting. Care should be taken to perform this accurately in order to secure the best performance and fuel economy.

When replacing the needle and seat assembly (inlet fitting), the float level must also be checked, as dimensional difference between the old and new assemblies may change the float level. Refer to carburetor adjustments for adjusting procedure.

  1. Install floats and fulcrum pin.
  2.  
  3. Install fulcrum pin retainer and baffle.
  4.  
  5. Install fuel inlet needle valve, seat and gasket in main body.
  6.  

AIR HORN
  1. Place the accelerator pump drive spring on pump plunger shaft then insert shaft into air horn. Compress spring far enough to insert "S'' link.
  2.  
  3. Install the pump lever, vacuum piston rod lifter and accelerator pump arm in the air horn.
  4.  
  5. Drop intake check ball into pump bore. Install baffle into main body. Place step-up piston spring in piston vacuum bore. Position a new gasket on the main body and install air horn.
  6.  
  7. Install air horn retaining screws and tighten alternately, a little at a time, to compress the gasket securely.
  8.  
  9. To qualify the step-up piston, adjust gap by turning the allen head calibration screws on top of the piston. See the adjustment section for proper measurement. Record number of turns and direction to obtain this dimension for this must be reset to its original position after the vacuum step-up piston adjustment has been made.
  10.  
  11. Carefully position vacuum piston metering rod assembly into bore in air horn making sure metering rods are in main metering jets. Then place the two lifting tangs of the plastic rod lifter under piston yoke. Slide shaft of the accelerator pump lever through rod lifter and pump arm. Install two locks and adjusting screws, but do not tighten until after adjustment is made.
  12.  
  13. Install fast idle cam and linkage. Tighten retaining screw securely.
  14.  
  15. Connect accelerator pump linkage to pump lever and throttle lever. Install retaining clip.
  16.  

CHOKE VACUUM DIAPHRAGM

Inspect the diaphragm vacuum fitting to insure that the passage is not plugged with foreign material. Leak check the diaphragm to determine if it has internal leaks. To do this, first depress the diaphragm stem, then place a finger over the vacuum fitting to seal the opening. Release the diaphragm stem. If the stem moves more than 1 / 16 inch in 10 seconds, the leakage is excessive and the assembly must be replaced.

Install the diaphragm assembly on the air horn as follows:

  1. Engage choke link in slot in choke lever.
  2.  
  3. Install diaphragm assembly, secure with attaching screws.
  4.  
  5. Inspect rubber hose for cracks before placing it on correct carburetor fitting. Do not connect vacuum hose to diaphragm fitting until after vacuum kick adjustment has been made.
  6.  
  7. Loosen choke valve attaching screws slightly. Hold valve closed, with fingers pressing on high side of valve. Tap valve lightly with a screwdriver to seat in air horn. Tighten attaching screws securely and stake by squeezing with pliers.
  8.  

CHOKE VACUUM KICK

The choke diaphragm adjustment controls the fuel delivery while the engine is running. It positions the choke valve within the air horn by action of the linkage between the choke shaft and the diaphragm. The diaphragm must be energized to measure the vacuum kick adjustment. Vacuum can be supplied by an auxiliary vacuum source.

Carter YF/YFA

See Figures 11, 12, 13 and 14

  1. Drill out the choke retainer rivet heads using a No. 30 ( 1 / 8 in.) drill bit. After the rivet heads are removed, drive out the remaining portion of the rivets with a 1 / 8 in. punch. This procedure must be followed exactly to retain the hole sizes.
  2.  
  3. Remove the screw holding the retainer.
  4.  
  5. Remove the retainer, thermostatic spring housing assembly, spring housing gasket and the locking/indexing plate.
  6.  
  7. Remove the vacuum break.
  8.  
  9. Disengage and remove the vacuum break connector link from the choke shaft lever.
  10.  
  11. Remove the sole-vac and the mounting bracket.
  12.  
  13. Remove the duty cycle solenoid from the air horn.
  14.  
  15. Remove the air horn attaching screws.
  16.  
  17. Remove the fast idle cam link.
  18.  
  19. Remove the air horn and gasket from the carburetor main body.
  20.  
  21. To remove the float from the air horn, hold the air horn bottom side up and remove the float pin and float.
  22.  
  23. Invert the air horn and catch the needle pin, spring and needle.
  24.  
  25. Remove the needle seat and gasket.
  26.  
  27. To remove the pump check ball and weight, turn the main body casting upside down and catch the accelerator pump check ball and weight.
  28.  
  29. Loosen the throttle shaft arm screw and remove the arm and pump connector link.
  30.  
  31. Remove the retaining screws and separate the throttle body from the main body.
  32.  
  33. Remove the wide open throttle switch and mounting bracket.
  34.  
  35. Remove the accelerator pump housing screws from the main body.
  36.  
  37. Lift out the pump assembly, pump lifter link and metering rod as a unit.
  38.  
  39. Disassemble the pump as follows:
    1. Disengage the metering rod arm spring from the metering rod.
    2.  
    3. Remove the metering rod from the metering rod assembly.
    4.  
    5. Compress the upper pump spring and remove the spring retainer cup.
    6.  
    7. Remove the upper spring, metering rod arm assembly and pump lifter link from the pump diaphragm shaft.
    8.  
    9. Compress the pump diaphragm spring and remove the pump diaphragm spring retainer, spring and pump diaphragm assembly from the pump diaphragm housing.
    10.  

  40.  
  41. Remove the low speed jet and the main metering jet.
  42.  
  43. Using a sharp punch, remove the accelerator pump bleed valve plug from outside the main body casting. Loosen the bleed valve screw and remove the valve.
  44.  
  45. Drill out and remove the tamperproof plug. After removing the plug, count the number of turns required to seat the idle mixture screw lightly. Remove the idle mixture screw and O-ring.
  46.  
  47. Thoroughly clean and inspect all components and replace any that are damaged, worn or malfunctioning. Check the idle mixture screw needle for scoring or damage and replace it if any grooves are noted.
  48.  
  49. Install the throttle body to the main body with the retaining srews, then install the idle mixture screw.
  50.  
  51. Install the low speed jet and main metering jet.
  52.  
  53. Install the pump bleed valve and spring.
  54.  
  55. Install the accelerator pump assembly.
  56.  
  57. Install the pump passage tube.
  58.  
  59. Install the throttle shaft arm and pump connector link and retaining screw.
  60.  
  61. Install the wide open throttle switch actuator.
  62.  
  63. Install the throttle shaft retaining bolt.
  64.  
  65. Install the wide open throttle switch and bracket.
  66.  
  67. To adjust the metering rod:
    1. Make sure the idle speed adjusting screw allows the throttle plate to close tightly in the throttle bore.
    2.  
    3. Press down on top of the pump diaphragm shaft until the assembly bottoms.
    4.  
    5. While holding the pump diaphragm down, adjust the metering rod by turning the metering rod adjusting screw counterclockwise until the metering rod just bottoms in the main metering jet.
    6.  
    7. Turn the metering rod adjusting screw clockwise one turn for final adjustment.
    8.  

  68.  
  69. Install the needle pin, spring, needle, seat, gasket and strainer.
  70.  
  71. Install the float and pin.
  72.  
  73. Invert the air horn assembly and check the clearance from the top of the float to the bottom of the air horn with the gauge. The float arm should be resting on the needle pin. Bend the float arm as necessary to adjust the float level.
  74.  
  75. Install the accelerator pump check ball and weight, then install the air horn and gasket to the main body.
  76.  
  77. Install the fast idle cam link.
  78.  
  79. Install the sole-vac and mounting bracket, then install the duty cycle solenoid and gasket.
  80.  
  81. Install the locking and indexing plate, spring housing gasket, thermostatic spring housing assembly, choke cover retainer and attaching screws.
  82.  
  83. Position the fast idle cam screw on the second step of the fast idle cam and against the shoulder of the high step. Adjust by bending the fast idle cam link to obtain the specified clearance between the lower edge of the choke plate and the carburetor air horn.
  84.  
  85. Position the fast idle screw on the top step of the fast idle cam.
  86.  
  87. Seat the vacuum break using a hand vacuum pump.
  88.  
  89. Apply a light closing pressure to the choke plate to position the plate as far closed as possible without forcing it. Measure the distance between the choke plate and the air horn. To adjust, bend the vacuum break connector link.
  90.  
  91. Adjust the sole-vac for curb idle speed. Refer to the Sole-Vac Adjustment procedure.
  92.  
  93. Set the idle mixture screw to the same number of turns as noted during disassembly. The idle mixture screw must be set to the exact number of turns as noted during disassembly. Install a new tamperproof plug.
  94.  
  95. Install the carburetor. To adjust the fast idle, turn the fast idle adjusting screw to contact the fast idle cam until the desired engine rpm is achieved. See the underhood emission control sticker for rpm specifications.
  96.  

Make sure the curb idle speed and mixture are adjusted to specifications before attempting the fast idle adjustment.

Click image to see an enlarged view

Fig. Fig. 11: Exploded view of the Carter YF carburetor used on the 4-134 engine



Click image to see an enlarged view

Fig. Fig. 12: Exploded view of the Rochester 2GC carburetor used on the 6-225 engine



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Fig. Fig. 13: Exploded view of the Carter YF carburetor used on the 6-232 and 6-258 engines



Click image to see an enlarged view

Fig. Fig. 14: Exploded view of the Carter YFA carburetor

Rochester 2SE/E2SE

See Figures 15 and 16

AIR HORN
  1. Invert the carburetor, then remove the plug covering the idle mixture needle as previously described.
  2.  
  3. Install the carburetor in a suitable holding stand.
  4.  
  5. Remove the primary and secondary vacuum break assemblies. Be sure to take note of the linkage positions for installation.
  6.  
  7. Remove the three screws from the mixture control solenoid. Remove the mixture control solenoid with gasket and discard the gasket.
  8.  
  9. Remove the two screws from the vent stack and remove the vent stack. Remove the intermediate choke shaft link retainer at the choke lever and discard it.
  10.  
  11. Remove the choke link and bushing from choke lever and save the bushing.
  12.  
  13. Remove the retainer and bushing from the fast idle cam link and discard the retainer.
  14.  

Do not remove fast idle cam screw and cam from the float bowl. If removed, the cam might not operate properly when reassembled. If needed, a replacement float bowl will include a secondary locknut lever, fast idle cam, and cam screw.

  1. Remove the retainer from the pump link. Do not remove the screw attaching the pump lever to the air horn assembly. When reassembled, the screw might not hold properly.
  2.  
  3. Remove the seven screw assemblies of various length that retain the air horn to the carburetor and remove the air horn assembly. Tilt the air horn to disconnect fast idle cam link from the slot in fast idle cam and the pump link from the hole in the pump lever.
  4.  
  5. Remove the cam link from the choke lever. Be sure to line up the "squirt'' on link with slot in lever.
  6.  
  7. Invert the air horn and remove the TPS actuator plunger. The TPS adjusting screw and plug should not be removed.
  8.  
  9. Remove the stakings that holds the TPS plunger seal retainer and pump stem seal retainer.
  10.  
  11. Remove the retainers and seals and discard them.
  12.  
  13. Further disassembly of the air horn is not required for cleaning purposes. The choke valve and choke valve screws, the air valve and air valve shaft should not be removed.
  14.  

Do not turn the secondary metering rod adjusting screw. The rod could come out of jet and possibly cause damage.

FLOAT BOWL
  1. Remove the accelerator pump, air horn gasket and pump return spring.
  2.  
  3. Remove the Throttle Position Sensor (TPS) assembly and spring. Inspect the TPS connector wires for broken insulation, which could cause grounding of the TPS.
  4.  
  5. Remove the upper insert and the hinge pin. Remove the float and lever assembly with the float stabilizing spring if used. Remove the float needle and pull clip.
  6.  
  7. Remove the lower insert, if used.
  8.  
  9. Remove the float needle seat and seat gasket.
  10.  
  11. Remove the jet and lean mixture needle assembly.
  12.  

Do not remove or change the preset adjustment of calibration needle in the metering jet unless the Computer Command Control system performance check requires it.

  1. Remove the pump discharge spring guide, using a suitable slide hammer puller only.
  2.  

Do not pry the guide. Damage could occur to the sealing surfaces, and could require replacement of the float bowl.

  1. Remove the spring and check ball, by inverting the bowl and catching them as they fall out.
  2.  
  3. Remove the fuel inlet nut and the fuel filter spring.
  4.  
  5. Remove the fuel filter assembly and discard it. Remove the filter gasket and discard it.
  6.  

CHOKE ASSEMBLY AND THROTTLE BODY
  1. Remove the choke cover as follows:
    1. Use a 5 / 32 in. (4mm) drill bit to remove the heads (only) from the rivets.
    2.  
    3. Remove the choke cover retainers. Remove the remaining pieces of rivets, using drift and small hammer.
    4.  
    5. Remove the electric choke cover and stat assembly.
    6.  

  2.  
  3. Remove the stat lever screw, Stat lever, intermediate choke shaft, lever and link assembly.
  4.  
  5. Remove the two screws and the choke housing.
  6.  
  7. Remove the four screws, and the throttle body assembly from the inverted float bowl.
  8.  
  9. Remove the gasket, pump link and line up the "squirt'' on link with the slot in the lever.
  10.  
  11. Count and make a record of the number of turns needed to lightly bottom the idle mixture needle (69), then back out and remove needle and spring assembly using Idle mixture socket tool J-29030-B or BT-7610-B or equivalent.
  12.  
  13. Do not disassemble throttle body further.
  14.  



Click image to see an enlarged view

Fig. Fig. 15: Exploded view of the Rochester 2GV carburetor



Click image to see an enlarged view

Fig. Fig. 16: Exploded view of the Rochester 2SE carburetor. the E2SE used on some models is similar

INSPECTION AND CLEANING
  1. Place the metal parts in immersion carburetor cleaner.
  2.  

Do not immerse idle stop solenoid, mixture control solenoid, throttle lever actuator, TPS, electric choke, rubber and plastic parts, diaphragms, and pump in the cleaner, as they may be damaged. Plastic bushing in throttle lever will withstand normal cleaning.

  1. Blow dry the parts with shop air. Be sure all fuel and air passages are free of burrs and dirt. Do not pass drill bits or wires through jets and passages.
  2.  
  3. Be sure to check the mating surfaces of casting for damage. Replace if necessary. Check for holes in levers for wear or out-of-round conditions. Check the bushings for damage and excessive wear. Replace if necessary.
  4.  

CARBURETOR REASSEMBLY
  1. Install the mixture needle and spring assembly using Idle mixture socket tool J-29030-B or BT-7610-B or equivalent. Lightly bottom the needle and back it out the number of turns recorded during removal, as a preliminary adjustment. Refer to idle mixture adjustment procedure in this section for the final idle mixture adjustment.
  2.  
  3. Install the pump link and a new gasket on the inverted float bowl.
  4.  
  5. Install the throttle body to the float bowl assembly and finger tighten the four retaining screws. If the secondary actuating lever engages the lockout lever, and linkage moves without binding, tighten retaining screws.
  6.  
  7. If the float bowl assembly was replaced, stamp or engrave the model number on the new float bowl in same location as on old bowl.
  8.  
  9. Place the throttle body and float bowl together on a suitable carburetor holding stand.
  10.  
  11. Install the choke housing on the throttle body, with the retaining screws.
  12.  
  13. Install the intermediate choke shaft, lever and link assembly.
  14.  
  15. Install the choke stat lever on the intermediate choke shaft. The intermediate choke lever must be upright.
  16.  
  17. Install the choke lever attaching screw in the shaft.
  18.  
  19. Install the gasket on the fuel inlet nut and install the new filter assembly in the nut.
  20.  
  21. Install the filter spring and then install the fuel inlet nut. Tighten the fuel inlet nut to 18 ft. lbs. (24 Nm).
  22.  


CAUTION
Tightening beyond this limit may damage gasket and could cause a fuel leak, which might result in personal injury.

  1. Install the pump discharge ball and spring.
  2.  
  3. Install a new spring guide and tap it until the top is flush with the bowl casting.
  4.  
  5. Install the needle seat with gasket. If used, lower the insert.
  6.  
  7. Install the jet and lean mixture needle assembly. Using lean mixture adjusting tool J-28696-10 or BT-7928 or equivalent, lightly bottom the lean mixture needle. Back it out 2 1 / 2 turns, as a preliminary adjustment.
  8.  

Only adjust the lean mixture needle screw if it was removed or touched during disassembly or if the Computer Command Control system performance check, made before disassembly, indicated an incorrect lean mixture needle setting:

  1. Bend the float lever upward slightly at the notch.
  2.  
  3. If used, install the float stabilizing spring on float. Install the hinge pin in float lever, with ends toward the pump well.
  4.  
  5. Install the needle with pull clip assembly on the edge of the float lever. Install the float and lever assembly in float bowl.
  6.  

Adjust the float level using Float Level T-Scale J-9789-90 or BT-8037 or equivalent.

  1. Install the upper insert over the hinge pin, with the top flush with the bowl. Install the TPS spring and the TPS assembly. The parts must be below the surface of the bowl.
  2.  
  3. Install the gasket over the dowels. Install the spring and pump assembly.
  4.  
  5. Install a new pump stem seal with the lip facing outside of carburetor and install the retainer. Be sure to stake it at new locations.
  6.  
  7. Install a new TPS actuator plunger seal with the lip facing outside of carburetor and install the retainer. Be sure to stake it at new locations.
  8.  
  9. Install the TPS plunger through the seal in the air horn. Use lithium base grease, liberally to pin, if used, where contacted by spring.
  10.  
  11. Install the fast idle cam link in the choke lever. Be sure to line-up the "squirt'' on link with slot in lever.
  12.  
  13. Rotate the cam to the highest position. The lower end of the fast idle cam link goes in cam slot, and the pump link end goes into the hole in the lever.
  14.  
  15. Hold the pump down, and than lower the air horn assembly onto the float bowl. Be sure to guide the pump stem through the seal.
  16.  
  17. Install the one of the air horn retaining screws, finger tight to hold the air horn in place.
  18.  
  19. Install the cam link in the slot of the cam. Install a new bushing and retainer to the link, with the large end of bushing facing the retainer. Check for freedom of movement.
  20.  
  21. Install the rest of the air horn retaining screws.
  22.  
  23. Install the spacer and a new seal, lightly coat the seal with automatic transmission fluid. Assemble the seal on the solenoid stem, touching the spacer.
  24.  
  25. Install a new retainer and a new gasket on the air horn. Install the mixture control solenoid lining up the stem with the recess in the bowl.
  26.  
  27. Install the solenoid retaining screws. Install the vent stack, with two retaining screws, (unless lean mixture needle requires on-vehicle adjustment).
  28.  
  29. Install a new retainer on the pump link. Adjust the air valve spring, if adjustable.
  30.  
  31. Install the bushing on the choke link. With the intermediate choke lever upright, install the link in the choke lever hole. Install the new link retainer.
  32.  
  33. The following procedures is for reassembly of any small components that have been removed from the carburetor, if part replacement is necessary or for any other reason.
    1. Install the idle stop solenoid, retainer and nut to the secondary side vacuum break bracket. Bend the retainer tab to secure nut.
    2.  
    3. Install the bushing to the link and the link to the vacuum break plunger. Install the retainer to the link.
    4.  
    5. Rotate the assembly, insert the end of the link in the upper slot of the choke lever. Install the bracket screws.
    6.  
    7. Install the idle speed device, retainer and nut to the primary side vacuum break bracket. Bend the retainer tab to secure the nut.
    8.  
    9. Install the bushing to the vacuum break link. Install the link to vacuum break plunger. Install the retainer to the link and the bushing to the air valve link. Install the link to the plunger and the retainer to the link.
    10.  

  34.  
  35. Rotate the vacuum break assembly (primary side) and insert the end of the air valve link into the air valve lever and the vacuum break link into the lower slot of the choke lever.
  36.  
  37. Install the bracket screws, vacuum hose between the throttle body tube and the vacuum break assembly.
  38.  
  39. Install the choke thermostat lever. Install the choke cover and thermostat assembly in the choke housing.
  40.  
  41. If the thermostat has a "trap'' (box-shaped pick-up tang), the trap surrounds the lever.
  42.  
  43. Line up the notch in the cover with projection on the housing flange. Install the retainers and rivets with rivet tool. If necessary, use an adapter. Adjust the choke as previously described.
  44.  

Autolite/Motorcraft 2100/2150

See Figures 17 and 18

DISASSEMBLY
  1. Remove the air cleaner anchor screw.
  2.  
  3. Remove the automatic choke rod retainer from the thermostatic choke shaft lever.
  4.  
  5. Remove the air horn attaching screws, lockwashers and carburetor identification tag. Remove the air horn and gasket.
  6.  
  7. Remove the choke rod by loosening the screw that secures the choke shaft lever to the choke shaft. Remove the rod and plastic dust seal from the air horn.
  8.  
  9. Remove the choke modulator assembly.
  10.  
  11. Remove the fast idle cam retainer.
  12.  
  13. Remove the choke shield.
  14.  
  15. Remove the thermostatic choke spring housing retaining screws and clamp, and the housing and gasket.
  16.  
  17. Remove the cam rod from the fast idle cam lever.
  18.  
  19. Remove the retaining screws and remove the choke housing and gasket.
  20.  
  21. Remove the fast idle cam.
  22.  
  23. Remove the thermostat lever retaining screw and washer. Remove the thermostatic choke shaft and fast idle cam lever. from the choke housing.
  24.  
  25. Pry the float shaft retainer from the fuel inlet seat. Remove the float, float shaft retainer and fuel inlet needle. Remove the retainer and float shaft from the float lever.
  26.  
  27. Remove the fuel inlet needle seat and gasket. Remove the main jets.
  28.  
  29. Remove the accelerator pump discharge screw, air distribution plate, booster venturi and gasket.
  30.  

Do not attempt to remove the tubes from the venturi assembly.

  1. Invert the main body and catch the accelerator pump discharge weight and ball.
  2.  
  3. Disconnect the accelerator pump operating rod from the overtravel lever. Remove the rod and retainer.
  4.  
  5. Remove the accelerator pump cover attaching screws. Remove the bowl vent bellcrank and bracket assembly, accelerator pump cover, diaphragm assembly and spring.
  6.  
  7. Remove the elastomer valve by grasping it firmly and pulling it out.
  8.  

If the valve tip breaks off during removal, be sure to remove the tip from the fuel bowl.Whenever the elastomer valve is removed, it must be replaced. It cannot be reused!

  1. Invert the main body and remove the power valve cover, gasket and screws. Remove the power valve. Remove and discard the gasket.
  2.  
  3. Remove the limiter caps from the idle mixture adjusting screws. Use a soldering gun to cut through the limiter caps. Remove the idle mixture adjusting screws and springs.
  4.  
  5. If equipped, remove the solenoid.
  6.  



Click image to see an enlarged view

Fig. Fig. 17: Exploded view of the Autolite 2100 carburetor used on the 8-304 engine



Click image to see an enlarged view

Fig. Fig. 18: Exploded view of the Motorcraft 2150 carburetor used on the 8-304 engine

ASSEMBLY
  1. Install the fast idle adjusting screw and spring on the fast idle lever.
  2.  
  3. If equipped, install the solenoid.
  4.  
  5. Install the fast idle lever assembly on the throttle shaft and install the retaining washer and nut.
  6.  
  7. Lubricate the tip of the new elastomer valve and install the tip of the elastomer valve into the accelerator pump cavity center hole. Using needle-nosed pliers, reach into the fuel bowl and grasp the valve tip. Pull the valve tip in until it seats in the pump cavity wall. Cut off the tip forward of the retaining shoulder. Remove the cut-off tip.
  8.  
  9. Install the bowl vent bellcrank and bracket assembly, accelerator pump cover, diaphragm assembly and spring. Install the accelerator pump cover attaching screws.
  10.  
  11. Connect the accelerator pump operating rod to the inboard hole of the pump actuating lever. Install the retainer.
  12.  
  13. Install the other end of the rod into the No.3 hole of the overtravel lever.
  14.  
  15. Invert the main body and install the power valve, gasket and screws. Install the power valve cover.
  16.  

Make sure the limiter stops in the cover are in position to provide a positive stop for the tabs on the idle adjusting limiters.

  1. Install the idle mixture adjusting screws and springs. Turn the screws in gently until they just touch the seat, then back each screw off 2 full turns.
  2.  

Do not install the limiter caps on the idle mixture adjusting screws at this time.

  1. Install the main jets.
  2.  
  3. Install the fuel inlet needle seat and gasket.
  4.  
  5. Install the retainer and float shaft on the float lever. Install the float, float shaft retainer and fuel inlet needle. Install the float shaft retainer on the fuel inlet seat.
  6.  
  7. Drop pump discharge ball into the passage in the main body.
  8.  
  9. Install the booster venturi and gasket.
  10.  
  11. Drop the discharge weight into the booster on top of the ball.
  12.  
  13. Install the air distribution plate and accelerator pump discharge screw.
  14.  
  15. Install the thermostatic choke shaft and fast idle cam lever on the choke housing. Install the thermostat lever retaining screw and washer.
  16.  

The bottom of the fast idle cam lever adjusting screw must rest against the tang of the choke shaft.

  1. Insert the choke shaft into the rear of the choke housing. Position the choke shaft so that the choke hole in the shaft is to the left side of the choke housing.
  2.  
  3. Install the cam rod on the fast idle cam lever.
  4.  
  5. Install the fast idle cam.
  6.  
  7. Install the fast idle cam retainer.
  8.  
  9. Install the choke housing and gasket. Install the retaining screws.
  10.  
  11. Install the thermostatic choke spring housing retaining screws and clamp, and the housing and gasket. Turn the cover 1 / 4 turn rich and tighten one screw.
  12.  
  13. Install the choke shield.
  14.  
  15. Install the choke rod. The lower end of the rod must protrude through the air horn. Install the rod and plastic dust seal from the air horn.
  16.  
  17. Install the air horn and new gasket. Install the air horn attaching screws, lockwashers and carburetor identification tag.
  18.  
  19. Install the automatic choke rod retainer on the thermostatic choke shaft lever.
  20.  
  21. Install the choke modulator assembly.
  22.  
  23. Make all necessary adjustments.
  24.  
  25. Install the air cleaner anchor screw.
  26.  

 
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