- Remove the carburetor.
- Remove the float bowl cover.
- Place a 27 / 32 " feeler gauge between the float arm and inlet needle and invert the carburetor.
- Tighten the seat screw to set the fuel level.
- Remove the feeler gauge.
- With the carburetor inverted, place an 11 / 64 " gauge between the top of the float and the inside surface of the float chamber. The gauge should pass lightly between the float and the chamber. If not, bend the tab on the float arm to adjust it.
- Upright the carburetor. Slide a 3 / 16 " gauge between the bottom of the float and float chamber. The gauge should pass lightly between the float and chamber. If not, adjust the float by bending the upright tang on the float lever.
- Install the float bowl cover using a new gasket.
- Install the carburetor using a new mounting gasket.
- Run the engine and check for leaks.
Fast Idle Cam Position
- Position the fast idle speed adjusting screw so that it contacts the second highest step of the cam. Move the choke valve toward the closed position with light pressure on the choke linkage.
- Insert a #52 drill bit between the upper edge of the choke plate and the wall of the air horn.
- If adjustment is necessary, bend the fast idle link at the angle until the specified drill fits between the choke plate and the wall of the air horn.
Fast Idle Speed
- Warm the engine by driving at least five miles.
- With the engine off and the transmission in Park or Neutral, open the throttle slightly.
- On models without the Clean Air Package, close the choke plate about 20°, then allow the throttle plates to close. The fast idle screw should now rest on the slowest speed step of the cam.
On models with the Clean Air Package, close the choke plate until the fast idle screw can be positioned on the second highest speed step of the cam.
- Start the engine.
- Turn the fast idle speed screw in or out until 700 rpm is obtained.
- Stopping the engine between adjustments is not necessary. However, be sure to position the fast idle speed screw on the cam after each speed adjustment.
Choke Vacuum Kick
- If the adjustment is to be made on the engine (with the engine running at curb idle), back off the fast idle screw until the choke can be closed to the kick position. Note the number of screw turns required so that the fast idle can be returned to the original adjustment.
- If the adjustment is to be made off the engine, open the throttle valve and move the choke to its closed position. Release the throttle first and then release the choke. Disconnect the vacuum hose from the carburetor body and apply a vacuum of at least 15 in.Hg.
- On models 1967 without the Clean Air Package but with manual transmission, insert a #30 drill bit between the choke valve and the wall of the air horn.
On 1967 models without the CAP but with automatic transmission, use a #38 drill bit.
On 1967 models with CAP, use a #28 drill bit.
On 1968-69 models, use a #30 drill bit.
On 1970-71 models, use a #39 drill bit on all carburetors except model #R-4641A. On that model use a #59 drill bit.
On 1972-73 models, except California, use a #58 drill bit.
On 1972-73 California models use a #62 drill bit with manual transmission; a #61 drill bit with automatic transmission.
- Apply sufficient closing pressure to the choke lever to provide a minimum valve opening without distorting the diaphragm link (which connects the choke lever to the vacuum diaphragm). Note that the cylindrical stem of the diaphragm will extend as its internal spring is compressed. This spring must be fully compressed for the proper measurement of the vacuum kick adjustment.
- Remove the drill bit. If a slight drag is not felt as the drill or gauge is removed, an adjustment of the diaphragm link is necessary to obtain the proper clearance. Shorten or lengthen the diaphragm link by carefully closing or opening the U-bend in the link until the correct adjustment is obtained.
- Refit the vacuum hose to the carburetor body (if it had been removed) and return the fast idle screw to its original location.
- With no vacuum applied to the diaphragm, the choke valve should move freely between its open and closed positions. If it does not move freely, examine the linkage for misalignment or interference which may have been caused by the bending operation. If necessary, repeat the adjustment to provide the proper link operation.
- Place the throttle plate in the curb idle position.
- It should be possible to insert a 3 / 32 " drill bit between the bowl vent and the seat. A 5 / 32 " drill but should [cf2]not fit.
- To make an adjustment, bend the vent rod at its horizontal portion.
- After the adjustment, be sure that the vent rod does not bind in the guide.
- Set the curb idle and mixture.
- Start the engine and position the throttle lever so that the actuating tab on the lever is contacting the stem of the dashpot [cf2]without depressing it!
- Allow about 30 seconds for the engine speed to stabilize. The engine speed should be 2,500 rpm.
- If not, loosen the locknut and turn the dashpot in or out as necessary.
- Hold the dashpot and tighten the locknut.