Publication #81-270-6001
TSB 14-04-87 May 4, 1987 Publication #81-270-6001filling the fuel bowl with clean fuel, using another accelerator pump plunger assembly. Hold the discharge check ball and weight down with a small brass rod and operate the pump plunger by hand. If the check ball and seat are leaking, no resistance will be experienced when operating the plunger (Fig. 16). If the valve is leaking, remove weight and stake the ball using a suitable drift punch. Exercise care when staking the ball to avoid damaging the bore containing the pump weight. After staking with the old ball, remove and replace with new ball from tuneup kit. Install weight and re-check for leaks.
(4) Install new gaskets on venturi cluster, then install cluster in position in main body (Fig. 13). Install cluster screws and tighten securely.
(5) Install main metering jets (Fig. 11).
(6) Install vacuum and mechanical power valves (2280 models only) using Special Tool C-4231 (Fig. 12). Be careful not to damage power valve needles. CAUTION: Be sure the Power Valves are installed in their proper location, Mechanical Valve on choke side and Vacuum Valve on Throttle Lever Side.
(7) A nitrophyl float can be checked for fuel absorption by lightly squeezing between fingers. If wetness appears on surface or float feels heavy (check with known good float), replace the float assembly.
(8) Install hinge pin in float assembly. Insert hinge through slot in float baffle with tabs on baffle pointing downward. Position assembly in hinge pin cradle in carburetor main body (Fig. 10).
(9) Place a new gasket on fuel inlet fitting and install assembly into main body, tighten securely to 180 inch pounds (20 N-m). Check float level. Refer to carburetor adjustments for adjusting procedure.
(10) Install feedback solenoid on 6280 models.
FIGURE 17 - SERVICING VACUUM POWER VALVE PISTON AND RETAINING RING:
Air Horn
(1) Test freeness of choke mechanism in air horn. The choke shaft must float free to operate correctly. If choke sticks in bearing bores, or appears to be gummed from deposits in air horn, a thorough cleaning will be required.
(2) Before installing the vacuum power valve assembly in bowl cover, be sure and remove all staking from the retainer cavity. Install the spring and piston in the vacuum cylinder, seat the retainer and stake lightly with suitable tool (Fig. 17). Compress piston to be sure no binding exists. If piston sticks or binds enough to hinder smooth operation, a new piston should be installed.
FIGURE 18 - SERVICING MECHANICAL POWER VALVE PUSH ROD:
(3) Install mechanical power valve push rod spring, push rod and "E" clip retainer. Push plastic cap on to push rod (2280 models only) (Fig. 18).
(4) Install accelerator pump plunger assembly through air horn and attach internal lever with C-link (2280 models only). On 6280 models, install new accelerator pump cup.
(5) Place a new gasket on air horn. Lower air horn straight down on main body; guiding accelerator pump plunger into its cylinder. Do not cut lip of plunger on sharp edge of cylinder. Install attaching screws and tighten to 25 inch pounds from center out.
TSB 14-04-87 May 4, 1987 Publication #81-270-6001
(6) Install accelerator pump arm, internal pump lever and pump operating shaft. On 2280 C link and internal pump lever must be attached to accelerator pump shaft. Install "E" clip (Fig. 5).
(7) To install fast idle connector link, engage plain end in slot of fast idle cam (from inside). Engage other end of rod in choke lever. With choke valve wide open, slide lever over choke shaft; (aligning flats). Install attaching lockwasher and nut. Tighten securely (Fig. 3).
(8) Install accelerator pump link in No. 1 hole closest to Air Horn and retain with cotter pin on throttle lever end.
(9) Engage choke diaphragm link in slot in choke lever. Install choke diaphragm assembly and secure with attaching screws (Fig. 2). Reinstall Vacuum Hose to Main Body.
(10) Install bowl vent assembly (Fig. 1).
(11) With pump links and levers installed, adjust the throttle blades to the closed position by backing out the idle speed screw.
(12) Set the distance from the top of pump lever to the top of bowl vent cover surface to .050 +/- .005 for 2280 models or .180 +/- .010 for 6280 models by bending the pump link. Check that wide open throttle can be reached without binding.
(13) Install gasket and bowl vent cover plate.
(14) Install Idle Stop Solenoid.
(15) Install air cleaner bolt and retainer assembly.
(16) Remove carburetor from repair stand.
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 actuated to measure the vacuum kick adjustment. Vacuum can be supplied by an auxiliary vacuum source.
Choke Unloader (Wide Open Kick) The choke unloader is a mechanical device to partially open the choke valve at wide open throttle. It is used to eliminate choke enrichment during cranking of an engine. Engines which have been flooded or stalled by excessive choke enrichment can be cleared by use of the unloader. Refer to carburetor adjustments for adjusting procedure.
Fast Idle Speed Fast idle engine speed is used to overcome cold engine friction, stalls after cold starts and stalls because of carburetor icing. Refer to carburetor adjustments for procedure.
Fast Idle Cam Position This adjustment is used to provide cam stop speeds at proper times during engine warmup.
TSB 14-04-87 May 4, 1987 Publication #81-270-6001
5. MECHANICAL POWER VALVE ADJUSTMENT (2280 MODELS ONLY)
(1) Remove bowl vent cover plate.
(2) Hold throttle in wide open position.
(3) Insert 5/64" Allen wrench in mechanical power valve adjustment screw.
(4) Push screw down and release to determine if clearance exists. Turn screw clockwise until clearance is zero.
(5) Adjust by turning screw counter clockwise one turn.
(6) Install bowl vent gasket and cover plate. IF ACCELERATOR PUMP ADJUSTMENT IS CHANGED, THIS ADJUSTMENT MUST BE RESET.
6. ACCELERATOR PUMP STROKE MEASUREMENT 6280 MODELS
(1) Remove bowl vent cover plate and gasket.
(2) With pump links and levers installed, adjust the throttle blades to the closed position by backing out the idle speed screw.
(3) Set the distance from the top of pump lever to the top of bowl vent cover surface to .180 +/- .010" by bending the pump link. Check that wide open throttle can be reached without binding.
(4) Install gasket and bowl vent cover plate.
(5) Reset Idle Speed.
TSB 14-04-87 May 4, 1987 Publication #81-270-6001
7. ACCELERATOR PUMP STROKE MEASUREMENT 2280 MODELS
(1) Remove bowl vent cover plate and vent valve lever and spring. Caution. Do not dislodge or lose vent valve lever retainer.
(2) With pump link in No. 1 inner hole and levers installed, adjust the throttle blades to the closed position by backing out the idle speed screw.
(3) Set the distance from the top of pump lever to the top of bowl vent cover surface to .050" +/- .005" by bending the pump link. Check that wide open throttle can be reached without binding.
(4) Install vent valve lever and spring and gasket and bowl vent cover plate.
(5) Reset Idle Speed.
NOTE: IF THIS ADJUSTMENT IS CHANGED, BOTH THE BOWL VENT AND THE MECHANICAL POWER VALVE ADJUSTMENTS MUST BE RESET.
8. IDLE RPM ADJUSTMENT (2280 MODELS)
Before checking or adjusting any idle speed, check ignition timing and adjust if necessary using the procedure shown in Group 8 Electrical. Disconnect and plug the vacuum hose at the EGR valve. Also disconnect and plug the vacuum hose from the carburetor at the heated air temperature sensor. Remove the air cleaner and disconnect and plug the 3/16 inch diameter control hose at the canister. Remove the PCV valve from the cylinder head cover and allow the valve to draw underhood air. Disconnect and plug vacuum hose at ESA module. Install tachometer. Start and run engine until normal operating temperature is reached.
RPM Chrysler No. Vendor No.
Refer to VECI Label 4288581 R-40245A
On a new vehicle (under 300 miles/500 km), reduce RPM settings by 75 RPM.
(1) Allow the engine to run for one minute for the engine speed to stabilize.
(2) If the engine rpm is not correct, turn the idle speed screw to obtain the correct idle rpm.
(3) Turn off engine. Unplug and reconnect vacuum hoses at EGR valve, canister, and ESA Module.
(4) Reinstall air cleaner and unplug and reconnect vacuum hose from carburetor to heated air temperature sensor on air cleaner. Remove tachometer and reinstall PCV valve. Idle speeds with the engine in normal operating condition (all hoses and wires connected) may vary from set speeds. DO NOT READJUST.
TSB 14-04-87 May 4, 1987 Publication #81-270-6001
(6) Return to idle and turn the engine off. Unplug and reconnect the vacuum hoses at the EGR valve and canister. Remove jumper wire.
(7) Model 6280 only-separate carburetor electrical connector from engine wire harness. Reinstall the green and blue wires in their correct positions. Reconnect to the engine wire harness.
(8) Reinstall the air cleaner and unplug and reconnect the vacuum hose from the carburetor to the heated air temperature sensor on the air cleaner. Remove the tachometer and reinstall the PCV valve. Idle speeds with the engine in normal operating condition (everything connected) may vary from set speeds. DO NOT READJUST.
11. CONCEALMENT PLUG REMOVAL
(1) Remove air cleaner.
(2) Disconnect all hoses from front of carburetor base.
(3) Center punch at a point 1/4 inch from end of mixture screw housing.
(4) Drill through at punch mark with 3/16 inch drill bit.
(5) Repeat operation on opposite side.
(6) Pry out plugs and save for reuse.
(7) Reinstall hoses and air cleaner.
BOWL VENT VALVE ADJUSTMENT 2280
(1) Remove bowl vent cover plate and vent valve lever spring. CAUTION: Do not dislodge or misplace vent valve lever retainer/pivot pin.
(2) With the throttle in the curb idle position, press firmly down on the vent valve lever where the spring seats; with another finger of the same hand, simultaneously press down on the vent valve tang until the vent valve is lightly seated (closed). CAUTION: If the carburetor is not on the engine, it must be on a raised fixture so as not to change, the curb idle throttle plate position.
(3) Using the other hand, measure the resulting gap between the contact surfaces of the vent valve lever and the vent valve tang with an appropriate gauge.
(4) Adjust by bending the end of the vent valve lever up or down until the specified gap (.030") is set.
(5) Install vent valve lever spring and bowl vent cover plate.
NOTE: THE BOWL VENT VALVE ADJUSTMENT MUST BE RESET IF THE ACCELERATOR PUMP ADJUSTMENT IS CHANGED.