If the carburetor is new to the engine, start at 1 -turns out (counterclockwise) from full in. Now start the engine and set the idle speed to around 850 rpm with the idle-speed screw.

Idling By: How To Set Carburetor Idle Mixture. Originally published in the April 1997 issue of Hot Rod magazine. ... The location of the idle mixture screws varies with each carburetor.

Turn the idle speed screw on each carb all the way out and back in, then 1-1/2 turns from dead-closed. Repeat this step a couple of times as necessary to make sure the screws are in the same ...