Initial Choke Valve Clearance/Fast Idle Cam Adjustment

Choke Cover:

1. Remove the choke cover shield, by grinding off the choke cover rivet heads. Some applications may have screws in place of the rivets, if so loosen the screws, but do not remove them. For those carburetors with rivets, proceed to step 2. For those carburetors with screws, proceed to step 5.

Choke Cover And Coil Assembly:

2. Remove the retainer, cover and coil, and gasket.
3. Then remove the remainder of the rivets.
4. Reinstall the gasket, cover and coil assembly, and the retainer, with replacement screws, in place of the rivets.
5. Open the throttle and rotate the choke cover until the choke valve is held closed. Tighten one retaining screw only for a preliminary adjustment.
6. Close the throttle with the fast idle speed adjustment screw on the top step of the fast idle cam.

Choke Diaphragm Vacuum:

7. Connect a hand held vacuum pump to the choke diaphragm, and apply a vacuum to hold the diaphragm against the set screw. There may be a noticeable air leak at this point, which is normal. Do not press on the linkage rods, to stop the air leak.

Choke Valve Clearance Adjustment:

8. Measure the clearance (A) between the lower edge of the choke valve and the top of the air horn. Check for the correct initial choke valve clearance setting. Adjust the clearance by turning the screw at the rear of the choke vacuum diaphragm.

Fast Idle Cam Linkage Adjustment:

9. Maintaining the vacuum from the hand held pump, push down on the the fast idle cam lever, until the fast idle speed adjustment screw is in contact with the second step of the fast idle cam, and against the shoulder of the high step.
10. Measure the clearance between the upper edge of the choke valve and the air horn wall. Check for the correct fast idle cam setting. Make the adjustment by turning the fast idle cam lever screw.
11. Install and tighten the remaining choke cover screws, and remove the vacuum pump. Reconnect the choke diaphragm vacuum hose.