Publication #81-370-6008
TSB 14-04-87 May 4, 1987 Publication #81-370-6008 Page 14-50
7. 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.
FIGURE 15 - TESTING ACCELERATOR PUMP DISCHARGE CHECK BALL AND SEAT:
FIGURE 16 - SERVICING VACUUM POWER VALVE PISTON AND RETAINING RING:
FIGURE 17 - SERVICING MECHANICAL POWER VALVE PUSH ROD:
Publication #81-370-6008 Revised TSB 14-04-87 May 4, 1987
(3) Install mechanical power valve push rod spring, push rod spring, push rod and "E" clip retainer. Push plastic cap on to push rod (2280 models only) (Fig. 8).
(4) Install accelerator pump plunger assembly through air horn and attach internal lever with Clink (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.
(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 screw (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.
TSB 14-04-87 May 4, 1987 Publication #81-370-6008
5. MECHANICAL POWER VALVE ADJUSTMENT 2280
(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 (AT IDLE) 6280
(1) Remove bowl vent cover plate and gasket.
(2) With pump link 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 #81-370-6008
12. PROPANE ASSISTED IDLE SET PROCEDURE (2280 AND 6280 MODELS)
RPM Chrysler No. Vendor No.
4324629 R-40214A
Refer to 4324631 R-40216A
VECI Label 4324632 R-40221A
4324633 R-40222A
On a new vehicle (under 300 miles/500 km) reduce RPM settings by 75 RPM. Tampering with the carburetor is a violation of Federal law. Adjustment of the carburetor idle air fuel mixture can only be done under certain circumstances as explained below. Upon completion of the adjustment, the concealment plugs must be replaced. This procedure should only be used if an idle defect still exists after normal diagnosis reveals no other faulty condition such as incorrect basis timing, incorrect idle speed, faulty hose or wiring connections, etc. Adjustment of the carburetor air fuel mixture should be performed after a major carburetor overhaul.
(1) Remove the concealment plug. Set the parking brake and place the transmission in neutral. Turn all lights and accessories off. Connect a tachometer to the engine. Start the engine and allow it to warm up on the second highest step of the fast idle cam until normal operating temperature is reached. Return the engine to idle and turn off engine.
(2) Remove air cleaner, disconnect and plug the vacuum hoses at the EGR valve and ESA computer. No vacuum is to be applied to the computer. Disconnect and plug canister purge hose at canister.
(3) Disconnect carburetor electrical connector.
(4) Remove the PCV valve from the cylinder head cover and allow the valve to draw underhood air.
(5) Start and run engine.
(6) Disconnect the vacuum supply hose from the choke diaphragm at the carburetor and install the propane supply hose in its place. Other connections at the tee must remain in place.
(7) With the propane bottle upright and in a safe location, open the propane main valve, Slowly open the propane metering valve until the maximum engine rpm is reached. When too much propane is added, engine rpm will decrease. "Fine tune" the metering valve to obtain the highest engine rpm.
(8) With the propane still flowing, adjust the idle speed screw on the solenoid to obtain the correct propane rpm. Again, "fine tune" the metering valve to obtain the highest engine rpm. If there has been a change in the maximum rpm, readjust the idle speed screw to the specified propane rpm.
(9) Turn off the propane main valve and allow the engine speed to stabilize. Slowly adjust the mixture screws by equal amounts, pausing between adjust- ments to allow engine speed to stabilize, to obtain the smoothest idle at the correct idle rpm.
(10) Turn on the propane main valve and "Fine tune" the metering valve to obtain the highest engine rpm. If the maximum engine speed is more than 25 rpm different than the specified propane rpm, repeat steps 8 through 12.
(11) Turn off propane main and metering valves. Remove the propane supply hose and reinstall the heated air sensor hose. Reinstall new concealment plugs. Reconnect vacuum line on ESA, reconnect carburetor electrical connector. Perform the Solenoid Idle Stop, Idle RPM, and Fast Idle Speed Adjustment Procedures.
13. 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.