Jeep CJ 1945-1970 Repair Information

Carburetors

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ADJUSTMENTS



Float and Fuel Level
4-134 ENGINES

The 4-134 engines utilize the Carter YF carburetor.

  1. Remove and invert the bowl cover.
  2.  
  3. Remove the bowl cover gasket.
  4.  
  5. Allow the weight of the float to rest on the needle and spring. Be sure that there is no compression of the spring other than by the weight of the float.
  6.  
  7. Adjust the level by bending the float arm lip that contacts the needle (not the arm) to provide:

    CJ-2A, CJ-3A models- 3 / 8 in. (9.5mm)
     
    1945-67 CJ-3B, CJ-5 and CJ-6 models- 5 / 16 in. (7.9mm)
     
    1968-70 CJ-5 and CJ-6 models- 17 / 64 in. (6.75mm)
     

  8.  

6-225 ENGINE

See Figures 1 and 2



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Fig. Fig. 1: Bend the float rod to adjust the float level to the specified value



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Fig. Fig. 2: Invert the air horn to measure the amount of float drop

The 6-225 engine utilizes the Rochester 2G carburetor.

The procedure for adjusting the float level of the two barrel carburetor installed on the V6 is the same as the procedure for the 4-134 up to Step 4.

The actual measurement is taken from the air horn gasket to the lip at the toe of the float. This distance should be 5 / 32 in. (4mm). To adjust the float level, bend the float arm as required.

The float drop adjustment is accomplished in the following manner: with the bowl cover turned in the upright position, measure the distance from the gasket to the notch at the toe of the float. Bend the tang as required to obtain a measurement of 1 7 / 32 in. (30.96mm).

6-226 ENGINE WITH CARTER MODEL YF
  1. Remove and invert the bowl cover.
  2.  
  3. Remove the bowl cover gasket.
  4.  
  5. Allow the weight of the float to rest on the needle and spring. Be sure that there is no compression of the spring other than by the weight of the float.
  6.  
  7. Adjust the level by bending the float arm lip that contacts the needle (not the arm) to provide 9 / 32 in. (7.14mm).
  8.  

6-226 ENGINE WITH CARTER MODEL WCD
  1. Remove the bowl cover and turn it upside down.
  2.  
  3. Remove the gasket.
  4.  
  5. With the tip of the float resting on the needle, measure the distance between the top of the float and the machined surface of the bowl casting. The gap should be 3 / 16 in. (4.76mm).
  6.  
  7. If not, adjust it by bending the float arms.
  8.  

6-226 ENGINE WITH CARTER MODEL WGD
  1. Remove the bowl cover and turn it upside down.
  2.  
  3. Remove the gasket.
  4.  
  5. With the tip of the float resting on the needle, measure the distance between the top of the float and the machined surface of the bowl casting. The gap should be 9 / 32 in. (7.14mm).
  6.  
  7. If not, adjust it by bending the float arms.
  8.  

6-230 ENGINE WITH HOLLEY 1920
  1. Remove the carburetor.
  2.  
  3. Slide float gauge J-10238 into position at the economizer body baffle and check the setting. The float should just touch the gauge.
  4.  
  5. If necessary, bend the float tab with needle nosed pliers. Do not allow the float tab to contact the float needle during this operation. Recheck the setting.
  6.  
  7. Slide the economizer diaphragm into position, making sure that the vacuum holes are aligned and that the stem is on the power valve.
  8.  
  9. Install and tighten the cover screws.
  10.  

6-230 ENGINE WITH HOLLEY 2415
  1. Park the vehicle on level ground and run the engine until it is idling at normal operating temperature.
  2.  
  3. With the engine idling, remove the fuel level check plug. The fuel level should be within 1 / 16 in. (1.6mm) of the bottom of the check plug port.
  4.  
  5. To adjust the level, loosen the fuel valve seat lock screw slightly with a screwdriver and turn the adjusting nut with a 5 / 8 in. wrench. Turn the nut clockwise to lower, and counterclockwise to raise, the fuel level. A 1 / 6 turn equals a 1 / 16 in. (1.6mm) change in the lever.
  6.  
  7. After adjustment, tighten the lockscrew and recheck the level.
  8.  

Fast Idle Linkage

This adjustment is performed with the air cleaner removed.

4-134 ENGINE

The 4-134 engines use the Carter YF carburetor.

With the choke held in the wide open position, the lip on the fast idle rod should contact the boss on the body casting. Adjust it by bending the fast idle link at the offset in the link.

6-225 ENGINE WITH ROCHESTER 2G

No fast idle speed adjustment is required. Fast idle is controlled by the curb adjustment screw. If the curb idle speed is set correctly and the choke rod is properly adjusted, fast idle speed will be correct.

6-226 ENGINE WITH CARTER MODEL WCD
  1. Loosen the choke lever clamp screw on the choke shaft.
  2.  
  3. Insert a 0.04 in. (1.01mm) feeler gauge between the lip of the fast idle cam and the boss of the flange.
  4.  
  5. Hold the choke valve closed tightly and take the slack out of the linkage by pressing the choke lever toward the closed position.
  6.  
  7. Hold it in this position and tighten the clamp screw.
  8.  
  9. With the choke valve tightly closed, tighten the fast idle adjusting screw until there is a gap of 0.016 in. (0.406mm) between the throttle valve and the air horn wall. Make sure that the fast idle screw is on the high step of the cam during this adjustment.
  10.  

6-226 ENGINE WITH CARTER MODEL WGD
  1. Remove the choke coil housing, gasket and baffle plate.
  2.  
  3. Crack the throttle and hold the choke plate closed. Then, close the throttle.
  4.  
  5. At this point, there should be a gap of 0.018-0.023 in. (0.457-0.584mm) between the throttle valve and air horn wall, opposite the idle port.
  6.  
  7. Adjust the gap by bending the choke connecting rod at the lower angle.
  8.  

6-230 ENGINE
  1. Connect a tachometer according to the manufacturer's instructions.
  2.  
  3. On vehicles equipped with a manual choke, adjust the choke wire to give maximum operation of the choke valve. With the engine off the choke fully open, adjust the fast idle screw to obtain a 0.030 in. (0.762mm) gap between the end of the screw and the cam.
  4.  
  5. On vehicles equipped with an automatic choke, run the engine to normal operating temperature. With the choke valve fully open and the engine idling in neutral, open the throttle slightly and rotate the fast idle cam until the fast idle screw contacts the second step of the fast idle cam. Release the throttle. The linkage pullback spring will cause the fast idle adjusting screw to hold the cam in this position. The tachometer should read 2100 rpm. If not, turn the adjusting screw until it does.
  6.  

Initial Choke Valve Clearance

See Figure 3



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Fig. Fig. 3: Identification of the choke rod adjustment components-Rochester 2GV carburetor

  1. Position the fast idle screw on the top step of the fast idle cam.
  2.  
  3. Using a vacuum pump, seat the choke vacuum break.
  4.  
  5. Apply light closing pressure in the choke plate to position the plate as far closed as possible without forcing it.
  6.  
  7. Measure the distance between the air horn wall and the choke plate. If it is not that specified in the Carburetor Specifications Chart, bend the choke vacuum break link until it is.
  8.  

Choke Setting
4-134 AND 6-225 ENGINES

The choke is manually operated by a cable that runs from the dash mounted control pull knob to the set screw on the choke actuating arm. To adjust the choke, loosen the set screw at the choke actuating lever and push in the dash knob as far as it will go. Open the choke plate as far as it will go and hold it with your finger while the set screw is tightened.

6-226 ENGINE

Loosen the choke cover screws and turn the cover, clockwise, until the indicator on the housing aligns with the notch on the casting. Tighten the screws.

Choke Unloader
4-134 AND 6-225 ENGINES

See Figure 4

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Fig. Fig. 4: Use a 1/4 in. diameter drill bit as a gauge between the choke plate and throttle bore wall

With the throttle held fully open, apply pressure on the choke valve toward the closed position and measure the clearance between the lower edge of the choke valve and the air horn wall. The setting should be 1 / 4 in. (6mm). Adjust by bending the tang on the fast idle lever, which is located on the throttle linkage.

Dashpot
INLINE 6-CYLINDER ENGINES

With the throttle set at curb idle position fully depress the dashpot stem and measure the clearance between the stem and the throttle lever. Adjust by loosening the lock nut and turning the dashpot.

INLINE 4-CYLINDER AND V6 ENGINES

See Figure 5

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Fig. Fig. 5: Identification of the dashpot adjustment components-Rochester 2GV carburetor

The adjustment is made with the engine idling. Loosen the dashpot locknut and turn the assembly until the plunger contacts the throttle lever without being depressed. Then, turn the assembly 2 1 / 2 turns against the lever, depressing the plunger. Tighten the locknut.

Accelerator Pump
6-226 ENGINE
  1. Place the pump connector link in the outer hole of the pump arm.
  2.  
  3. Back out the throttle lever setscrew until the throttle plates seat in their bores. Make certain that the fast idle adjusting screw is not holding the throttle open.
  4.  
  5. Place pump travel gauge, T109-117S, or its equivalent, inverted on the edge of the dust cover boss on the bowl cover.
  6.  
  7. Turn the knurled nut of the gauge until the finger just touches the upper end of the plunger shaft. The measured distance should be 1 / 2 in. (13mm) from the dust cover boss to the top of the plunger. This corresponds to an indicated gauge number of 33. Adjust by bending the link at the upper bend.
  8.  

Metering Rod
6-226 ENGINE WITH CARTER MODEL WCD

See Figure 6

  1. Perform a pump adjustment.
  2.  
  3. Counting the number of threads involved, back out the throttle lever screw until the throttle plates are seated in their bores.
  4.  
  5. Press down on the vacumeter link until the metering rods bottom.
  6.  
  7. In this position, move the metering rod arm until the lip contacts the vacumeter link.
  8.  
  9. Hold it in place and tighten the metering rod setscrew.
  10.  

6-226 ENGINE WITH CARTER MODEL WGD
  1. Perform a pump adjustment.
  2.  
  3. Counting the number of threads involved, back out the throttle lever screw until the throttle plates are seated in their bores.
  4.  
  5. Press down on the vacumeter link until the metering rods bottom.
  6.  
  7. In this position, move the metering rod arm until the lip contacts the vacumeter link.
  8.  
  9. Hold it in place and tighten the metering rod setscrew.
  10.  

REMOVAL & INSTALLATION



All Engines

See Figures 6 through 19

  1. Remove the air cleaner from the top of the carburetor.
  2.  
  3. Remove all lines and hoses, noting their positions to facilitate installation.
  4.  



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Fig. Fig. 6: While adjusting the metering rod, it is necessary to depress the diaphragm shaft



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Fig. Fig. 7: For L-head 4-134 engines, disconnect the fuel line from the carburetor ...



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Fig. Fig. 8: ... then detach the throttle cable from the throttle lever



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Fig. Fig. 9: Remove the rear hold-down nut and loosen the front hold-down nut ...



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Fig. Fig. 10: ... then remove the front nut while lifting the carburetor off the manifold



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Fig. Fig. 11: Make certain to remove the old gasket from the carburetor or manifold



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Fig. Fig. 12: On F-head 4-134 engines, use 2 wrenches to loosen the fuel line fitting ...



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Fig. Fig. 13: ... then pull the fuel line from the carburetor inlet fitting



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Fig. Fig. 14: If equipped, detach the vacuum wiper booster line from the carburetor base



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Fig. Fig. 15: Remove the cotter pin to detach the throttle cable from the carburetor lever



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Fig. Fig. 16: Loosen the choke cable clamp screw ...



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Fig. Fig. 17: ... then slide the cable out of the carburetor lever



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Fig. Fig. 18: Remove the carburetor mounting nuts ...



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Fig. Fig. 19: ... and lift the carburetor off of the manifold/cylinder head

  1. Remove all throttle and choke linkage at the carburetor.
  2.  
  3. Remove the carburetor attaching nuts which hold it to the intake manifold.
  4.  
  5. Lift the carburetor from the engine along with the carburetor base gasket. Discard the gasket.
  6.  
  7. Install the carburetor in the reverse order of removal, using a new base gasket.
  8.  

To avoid any distortion of the carburetor body, always tighten the nuts alternately, in a crisscross pattern to 182 inch lbs. (20 Nm).

See Figures 20, 21 and 22



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Fig. Fig. 20: Exploded view of the Rochester 2GC carburetor used on 6-225 engines



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Fig. Fig. 21: Exploded view of the Rochester 2GV carburetor



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Fig. Fig. 22: Exploded view of the Carter YF carburetor used on 4-134 engines

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 disassembled, 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:



Check the float needle and seat for wear. If wear is found, replace the complete assembly.
 
Check the float hinge pin for wear and the float(s) for dents or distortion. Replace the float if fuel has leaked into it.
 
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.
 

Throttle shafts and bushings are not included in overhaul kits. They can be purchased separately.



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.
 
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.
 
Check the bowl cover for warped surfaces with a straightedge.
 
Closely inspect the valves and seats for wear and damage, replacing as necessary.
 
After the carburetor is assembled, check the choke valve for freedom of operation.
 

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 hold-down 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.

 
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