See Figure 1
- 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 0.070" drill bit between the upper edge of the choke plate and the wall.
- 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.
See Figure 2
- 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.
- 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.
- Insert a 0.130" drill bit between the choke valve and the wall of the air horn.
- 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.
See Figure 3
- Hold the throttle valve in the wide open position.
- Insert a 0.250" drill bit between the upper edge of the choke valve and the wall of the air horn for model R-40132; 0.150" for all other carburetors.
- With a finger pressing lightly against the choke plate, a slight drag should be felt as the drill is being withdrawn.
- If adjustment is necessary, bend the unloader tang on the throttle lever until the correct opening is obtained.
See Figure 4
- Remove the bowl vent cover plate and vent valve lever spring. Be careful not to dislodge or lose the vent valve retainer.
- Make sure that the pump connector rod is in the inner slot of the pump arm.
- Position the throttle at curb idle.
- Place a straightedge on the bowl vent cover surface of the air horn over the accelerator pump connector rod in the center of the bowl.
- Bend the accelerator pump connector rod until the lever surface is flush with the air horn surface on 1985 models; 0.135" above the casting on 1986-87 models.
- Install the vent valve lever spring and bowl vent cover plate.
If this adjustment is changed, both the bowl vent and the mechanical power valve adjustment must be reset.Fast Idle Speed
See Figure 5
- Run the engine to normal operating temperature.
- Disconnect and plug the EGR vacuum line and distributor advance vacuum line. Disconnect and plug the vacuum advance line at the distributor. Disconnect and plug the carburetor vacuum line at the heated air temperature sensor. Remove the air cleaner and plug the 3 / 16 " vacuum line at the canister. Remove the PCV valve from the rocker cover and allow it to draw fresh air.
- Set the parking brake and place the transmission in Neutral.
- With the engine off, open the throttle and place the fast idle adjusting screw on the second highest speed step of the cam.
- Start the engine. Let the engine speed stabilize.
- Turn the fast idle speed screw in or out until the engine speed listed on the underhood sticker is reached.
- Reposition the screw on the cam after each adjustment to provide the correct closing torque.
- Reconnect the vacuum hoses and install the air cleaner.
See Figure 6
- Remove the carburetor.
- Remove the air horn.
- Invert the carburetor body. THE PUMP INTAKE CHECK BALL WILL DROP OUT. BE SURE TO CATCH IT!
- Allow the weight of the floats to rest on the needle valve. Hold your finger against the hinge pin retainer to fully seat it in the float pin cradle.
- Using a straightedge, measure the gap between surface of the float bowl to the toe of each float. The gap should be 9 / 32 " +-1 / 32 ".
- If adjustment is necessary, bend the float tang. Bend either float arm to equalize the individual float positions.