If the accelerator is moved slightly open the fast idle cam will drop a notch and move toward curb warm idle rpm. You cannot adjust the idle mixture if the idle speed is too fast.
1954 Buick Stromberg Carburetor Fast Idle Cam Adjustment
Fast idle cam adjustment. Turn the screw clockwise 14 of a turn at a time until the rpm starts to drop. To get to the fast idle screw you have to open the throttle all the way and only then will you see it swing into view and be accessible. If necessary adjust the fast idle cam screw a until the alignment mark is centered on the lever roller. As the engine warms up the choke spring tension will be reduced. At that point you can go ahead and snug those screws back up and thats going to give you a good starting point to make adjustments from. Holley set up and adjust step by step duration.
Measure the clearance between the lever roller and the top of the fast idle cam using a feeler gauge. You do not want to aggressively throttle the engine to get the fast idle to drop. Unscrew the fast idle adjuster screw until it is clear of the stepped cam. Fast idle and choke has to be set with the engine cold so it can be a bit of a pain to get it right since you pretty well have let it cool completely off between adjustments. How to adjust the choke and fast idle on holley carburetors holleyperformance. High speed idle cam discussion duration.
Back it off about one turn. Set the idle to specification. Start the engine and let it warm to operating temperature or do the repair after a few errands that you needed to run anyway. Turn the screw counter clockwise 14 of a turn. Slightly crack the throttle open unload the fast idle cam and turn the choke cap clockwise until you see the choke plate open. Screw it in until it just touches the very bottom of the stepped cam not on any of the steps themselves.
Make sure that the choke is fully open and the fast idle adjuster screw is resting on the very bottom of the stepped cam. Adjust by switching between each screw. Now screw it in another 14 turn. Then rotate it back slowly until the choke plate just comes closed.
Gallery of Fast Idle Cam Adjustment
