You cannot adjust the idle mixture if the idle speed is too fast. Adjust by switching between each screw.
Solex 34 Pict 3 Carburetor Adjustment And Tune Up Procedures
Fast idle cam adjustment. Back it off about one turn. Then rotate it back slowly until the choke plate just comes closed. Measure the clearance between the lever roller and the top of the fast idle cam using a feeler gauge. Screw it in until it just touches the very bottom of the stepped cam not on any of the steps themselves. Holley set up and adjust step by step duration. How to adjust the choke and fast idle on holley carburetors holleyperformance.
Now screw it in another 14 turn. Unscrew the fast idle adjuster screw until it is clear of the stepped cam. Slightly crack the throttle open unload the fast idle cam and turn the choke cap clockwise until you see the choke plate open. You do not want to aggressively throttle the engine to get the fast idle to drop. Start the engine and let it warm to operating temperature or do the repair after a few errands that you needed to run anyway. 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.
Make sure that the choke is fully open and the fast idle adjuster screw is resting on the very bottom of the stepped cam. 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. Turn the screw clockwise 14 of a turn at a time until the rpm starts to drop. If necessary adjust the fast idle cam screw a until the alignment mark is centered on the lever roller. 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.
Turn the screw counter clockwise 14 of a turn. Set the idle to specification. High speed idle cam discussion duration. If the accelerator is moved slightly open the fast idle cam will drop a notch and move toward curb warm idle rpm.
Gallery of Fast Idle Cam Adjustment
