Carburetor Modification & Procedures

CARBURETOR MODIFICATIONS AND ADJUSTMENTS (ALL MANUAL TRANSMISSION VEHICLES FROM 8/84 TO 12/86 PRODUCTION)

The following procedures may further improve hesitation conditions.


1. INSPECT FLOAT LEVEL



Fuel level should be adjusted in the upper range of the SIGHT GLASS. If fuel level is below the mid-point of the window, the float level should be adjusted to specifications.
2. REMOVE CARBURETOR



(a) Before disconnecting the vacuum hoses, use tags to identify how the vacuum hoses should be reconnected.

(b) Remove the carburetor from the engine.

(c) After removing the carburetor, cover the intake manifold with a clean cloth.
3. REMOVE MIXTURE ADJUSTING SCREW PLUG (MAS PLUG)



(a) Plug each carburetor vacuum port to prevent entry of steel particles when drilling.

(b) Mark the center of the plug with a center punch.



(c) Drill a 1/4 in. (6.0 mm) hole in the center of the plug.

NOTE:

There is only 0.04 in. (1 mm) clearance between the plug and idle mixture screw. Drill the plug carefully and slowly to avoid drilling into the idle mixture screw. The drill may force the plug out at this time.



(d) Through the hole in the MAS plug, turn the mixture adjusting screw all the way in using a small tip screwdriver.


NOTE:

Be careful not to damage the screw tip by tightening the screw too tight.



(e) Use a 5/16 in. (7.0 mm) drill to force the plug out.

(f) Unscrew the mixture adjusting screw 3 complete turns.
4. REMOVE AIR HORN ASSEMBLY






(a) Disconnect the choke link.

(b) Disconnect the accelerator pump connecting rod.

(c) Remove the accelerator pump arm pivot bolt and remove the pump arm.

(d) Remove the eight air horn screws.

(e) Lift the air horn with the gasket from the carburetor body.
5. REPLACE THE POWER PISTON SPRING



(a) Remove the power piston retainer (1), power piston (2) and spring.

(b) Replace the power piston spring with the one supplied with the kit.

(c) Reinstall the power piston with spring into the bore.

(d) Reinstall the power piston retainer.
6. REPLACE THE PRIMARY MAIN JET



(a) Remove the TP lever

(b) Remove the primary main passage plug, primary main jet and gasket.

(c) Install the new primary main jet and passage plug with new gaskets.

(d) Install the TP lever.
7. REPLACE AAP HOUSING



(a) Remove the three screws attaching the AAP housing.

(b) Carefully remove the AAP housing from the carburetor body so the AAP diaphragm is not damaged.

(c) Install the new AAP Housing spring and diaphragm.
8. RE-ASSEMBLE THE AIR HORN AND CARBURETOR BODY



(a) Reinstall the air horn with the gasket to the carburetor body.

(b) Install the eight air horn attaching screws.
9. REPLACE THE MECHANICAL ACCELERATOR PUMP ARM (1986 AND 1987 MODELS ONLY)



a) Replace the pump arm and connecting rod with the new part.

b) Install the pump arm to the air horn and attach the pump connecting rod.
10. REPLACE THE SECONDARY THROTTLE VALVE DIAPHRAGM SPRING



a) Remove two diaphragm retaining screws (3).

b) Disconnect the throttle springs
(4) and (5).

c) Remove the diaphragm assembly and gasket.

d) Remove the four small screws
(6) from the diaphragm housing.

e) Replace the secondary throttle valve diaphragm spring (7) with the new spring.

f) Assemble the secondary throttle valve diaphragm.

9) Install the diaphragm to the
carburetor body with a new diaphragm housing cap gasket.

h) Connect the throttle spring

(4) and (5).



11. ADJUST THE SECONDARY THROTTLE VALVE KICK-UP CLEARANCE
Note: Use SST 09240-00020 to make adjustment.



With the primary throttle valve fully opened, adjust the kick-up clearance (between the secondary throttle valve and body) to 0.022-0.025 in. (0.55-0.65 mm) by bending the secondary throttle lever.
12. ADJUST THE 2ND CHOKE BREAKER ANGLE






(a) Apply vacuum to choke breaker diaphragms A and B.

(b) Adjust the choke valve angle to

58~ by turning the diaphragm adjusting screw.
13. RE-INSTALL CARBURETOR
a) Re-install the carburetor.

b) Reconnect the vacuum hoses to the proper locations. Refer to the Vacuum Hose Information label under the hood.
14. RE-INSTALL AIR CLEANER
15. REPLACE THE HIGH ALTITUDE COMPENSATOR JET



Replace the original jet with the one included in the field fix kit.
16. INSTALLATION OF THE V.T.V.






a) Cut the vacuum hose between the EGR modulator and the EGR valve

(A).


b) Install the VTV in the above mentioned vacuum hose as shown below.
17. WARM ENGINE TO OPERATING TEMPERATURE

18. INSPECT AND ADJUST ENGINE TIMING

MODEL YEAR PRODUCTION RANGE TIMING

1985 All 3~ BTDC

1986 8/85- 2/86 3~ BTDC
3/86- 7/86 5~ BTDC

1987 8/86-12/86 5~ BTDC