See Figures 87 through 101

1.       Remove the carburetor from the engine.

If idle mixture screws plugs are going to be drilled out, refer to Engine Performance & Tune-Up for the necessary service procedure.

Fig. 87: Remove the compensator only if it is necessary to replace it

Fig. 88: The suction chamber adjusting pin plug can be removed using two small prybars

Fig. 89: With the plug removed, the adjusting pin can now be shaken out

Fig. 90: Be careful not to damage the suction chamber when removing it

Fig. 91: Using improper tools or excessive force can easily damage brass components

Fig. 92: The adapter is usually secured by three screws

2.       Remove the air cleaner support.

3.       Remove the throttle position switch.

4.       Remove the fuel cut solenoid valve and discard the gasket. Remove the clamps retaining the wires.

5.       Remove the fuel nipple union and gaskets.

6.       If the compensator must be replaced, remove the attaching screws and separate it from the carburetor body.

7.       Install a small bolt into the suction chamber adjusting pin plug.

8.       Pry off the plug with two small prybars, then remove the O-ring.

9.       Turn the carburetor over, then shake the pin out.

10.   Remove the three suction chamber attaching screws. Pull out the suction chamber, spring and piston from the carburetor body.

11.   Remove the pump arm clip, pivot screw and pump arm. Remove the bushing and spring from the connecting rod.

12.   Remove the fuel heater wire from the clamp.

13.   Remove the float bowl attaching screws, union nipple clamp, throttle valve solenoid, wire clamp, washer, number plate, EGR vacuum modulator bracket and the float bowl.

14.   Remove the pump plunger and boots.

15.   Remove the float pivot pin, float and needle assembly.

16.   Remove the float bowl gasket, needle valve seat and gasket.

17.   Remove the throttle positioner.

18.   Remove the adapter and gasket.

19.   Remove the three bolts and the vacuum passage bolt. Separate the carburetor body from the carburetor flange.

20.   Clean all the disassembled parts before inspecting them. Wash and clean the cast metal parts with a soft brush in carburetor cleaner. Clean off the carbon around the throttle plates. Wash the other parts thoroughly in cleaner. Blow all dirt and other foreign matter from the jets, fuel passages and restrictions within the body.

21.   Inspect the float and needle valve. Check the pivot pin for scratches and excessive wear. Inspect the float for breaks in the lip and wear in the pivot pin holes. Check the needle valve plunger for wear or damage and the spring for deformation. The strainer should be checked for rust or breaks.

22.   Inspect the suction chamber and piston for scratches, damage and wear. Do the same for the metering needle.

23.   Inspect the fuel heater and cold mixture heater. Using an ohmmeter, measure the resistance between the terminals of the float bowl wiring connector. It should be between 2-6 ω. If not, replace the float bowl. Measure the resistance between the terminals of the cold mixture heater. It should be between 0.5-2.2 ω. If not, replace the float bowl.

To install:

24.   Install the adapter with a new gasket.

25.   Install the throttle positioner.

Fig. 93: Inspect the float and needle valve assembly for signs of wear or damage

Fig. 94: The suction chamber, piston and metering needle should also be inspected for damage or wear

Fig. 95: Using an ohmmeter to test the fuel heater

Fig. 96: Checking the resistance of the cold mixture heater

Fig. 97: Be careful not to damage the pin clip when installing it onto the needle valve

26.   Install the needle valve seat over a new gasket into the fuel inlet.

27.   Install the needle valve, spring and plunger onto the seat. Then install the float and pivot pin.

28.   Perform the float adjustment procedures. After adjusting the float, remove the float, plunger, spring and needle valve.

29.   Place a new gasket on the carburetor body.

30.   Assemble the pin clip onto the needle valve, then reinstall needle valve assembly, float and pivot pin. Insert the float lip between the plunger and clip when installing the float.

31.   Install the boots and pump plunger.

32.   Assemble the pump damping spring to the float bowl.

33.   Install the float bowl, union nipple clamp, solenoid valve clamp, EGR vacuum modulator bracket and number plate with the attaching screws.

34.   Install the pump arm with the pivot screw. Install the retaining clip.

35.   Install the suction piston into the carburetor body. Then, install the spring and suction chamber with the attaching screws.

36.   Insert the suction chamber adjusting pin into the groove on the suction piston. Install a new O-ring with the plug.

37.   Install the compensator with a new gasket. Be sure to install the throttle position switch wiring clamp and tighten the screws using the correct sequence.

38.   Install the wax back springs. Be sure the spring's hooks do not overlap.

39.   Install the union nipple with new gaskets.

40.   Install the solenoid valve with a new gasket into the carburetor body.

41.   Connect the solenoid valve and throttle position switch wire to the clamp. Install the two clamps.

42.   Install the throttle position switch and air cleaner support.

43.   With the carburetor still on the bench, move the various linkages by hand, checking for smooth operation. Follow the adjustment procedures outlined earlier.

44.   Reinstall the carburetor on the intake manifold, following the procedure outlined earlier.

45.   Start the engine and allow it to warm up normally. During this time, pay careful attention to the high idle speed, the operation of the choke and its controls and the idle quality. If you worked carefully and accurately, and performed the bench set-up properly, the carburetor should need very little adjustment after reinstallation.

Fig. 98: Installing the float and needle valve assembly

Fig. 99: The float bowl screws should be tightened in steps, using a criss-cross pattern

Fig. 100: Insert the suction pin into the groove on the suction piston. Install a new O-ring and plug as well

See Figure 102

Fig. 101: If the compensator was removed, tighten the screws using this sequence

Fig. 102: Exploded view of the carburetor used on 3E engines

Fig. 3: Idle speed adjustment screw on 3E carbureted engines

Fig. 8: Fast idle adjustment on 3E engines

Fig. 14: Mixture adjusting screw on 3E models

Fig. 16: Mixture adjusting screw depth on 3E models

3E ENGINES

1.       Disconnect the vacuum hose from the TP diaphragm (A) and plug the hose end.

2.       Disconnect the vacuum hose from the EGR valve and plug the hose end.

3.       Check that the TP is set at the first step. Engine speed should be at 1,100 rpm.

4.       Adjust the TP screw, if necessary.

Adjustment must be made with the cooling fan OFF.

5.       Reconnect the vacuum hose to diaphragm (A).

6.       Disconnect and plug the vacuum hose from diaphragm (B).

7.       Check that the TP is set at the second step. Engine speed should be at 1,800-2,200 rpm.

8.       Reconnect the vacuum hose to the diaphragm and the EGR valve.

Fig. 50: Disconnecting and plugging the vacuum hose from diaphragm A

Fig. 51: The vacuum hose from the EGR valve should be disconnected and plugged as well

Fig. 52: Throttle positioner adjusting screw location on 3E engines

3E ENGINES

1.       Measure the length of the pump stroke.

2.       Length of the pump stroke should be 0.217 in. (5.5mm).

3.       Adjust, if necessary, by bending the connecting link.

Fig. 40: Checking the pump stroke on 3E engines

Fig. 41: On 3E engines, bend the connecting link here to adjust pump stroke

3E ENGINES

1.       Apply vacuum to the throttle positioner diaphragms.

2.       With the throttle valve fully opened, measure the piston lift stroke.

3.       It should be more than 0.31 in. (8mm).

Fig. 31: Checking the piston lift stroke on 3E engines

3E ENGINES

1.       Set the fast idle adjusting cam to the roller of the throttle lever.

2.       Measure the throttle valve angle. It should be as follows:

a.       Manual transaxle-18.7 degrees from horizontal

b.       Automatic transaxle-19 degrees from horizontal

3.       Adjust by turning the No. 1 fast idle adjusting screw.

4.       Separate the fast idle adjusting cam from the fast idle lever.

5.       Using a screwdriver, pry open a gap of at least 0.20 in. (5mm) between the fast idle cam and the cold enrichment rod. Allow the gap to close again.

6.       Flush out the compensator water pipe for 2-3 minutes with water. Do not allow water to enter the carburetor.

7.       Apply vacuum to the throttle positioner diaphragms and measure the throttle angle.

8.       Compare the temperature of the water used to flush the compensator to the chart and use the corresponding angles.

9.       Adjust by turning the No. 2 fast idle adjusting screw.

Fig. 20: Setting the fast idle adjusting cam and checking the throttle valve angle on 3E engines

Fig. 21: No. 1 fast idle adjusting screw location on 3E engines

Fig. 22: Opening a gap between the fast idle cam and cold enrichment rod

Fig. 23: Check the temperature of the water being used to flush the compensator

Fig. 24: Water temperature/throttle valve angle correlation chart

Fig. 25: No. 2 fast idle adjusting screw location

Fig. 9: Checking the throttle valve opening on 3E engines

Fig. 10: Bend the throttle lever stopper on 3E engines to adjust the throttle valve opening

Fig. 5: Checking the float level lowered position on 3E engines

Fig. 2: Checking the float level raised position on 3E engines

Float Level

See Figures 1 through 6

Performed on 3A, 3A-C and 3E engines.

It will be necessary to remove the air horn from the carburetor to gain access to the float. Follow the procedures outlined in carburetor overhaul.

1.       Remove the float, needle valve, spring and plunger.

2.       Remove the pin clip from the needle valve.

3.       Install the needle valve, spring and plunger onto the seat.

4.       Install the float and pivot pin.

5.       Allow the float to hang down by it's own weight. Check the clearance between the float tip and the carburetor body without the gasket on the air horn.

6.       Clearance should be as follows:

a.       3E engines-0.169 in. (4.3mm)

7.       Adjust, if necessary, by bending the portion of the float lip marked (A) in the illustration.

8.       Lift up the float and check the clearance between the needle valve plunger and the float lip.

9.       Clearance should be as follows:

a.       3E engines-0.035-0.043 in. (0.9-1.1mm)

10.   Adjust by bending the portion of the float lip marked (B) in the illustration.

11.   After adjusting the float level, remove the float, plunger, spring and needle valve.

12.   Assemble the pin clip onto the needle valve.

13.   Install the needle valve assembly, float and pivot pin. Assemble the carburetor following the procedures in carburetor overhaul.