What kind of carb does the 76 c10 4x4 come with need to adjust
mcdevito75 here, The fast idle is needed when the engine is cold to make the air and fuel mixture rich to keep the engine running while cold, the carb. choke doew this with a bi-metalic spring in that balck round box on the side of the carb, a screw also hepls keep the choke closed until warm up, this screw can be adjusted tpo control how tight it holds the choke cloesed, here"s how to adjust this screw to slow fast idle speed, Locate on the carb, where the gas pedal connects, have a friend operate the gas pedal with the engine off, once you locate the linkage, you"ll also see 2 screws with springs around them, 1 is for fast idle the other for regular idle, you want the fast idle screw, notice this screw will lay against and Half moon shaped tab, while the other screw lays against a shaft, you need the screw that lays against the half moon shaped tab. Start the engine and step on the gas pedal slightly and relaease, at the screw that lays against this half moon, simply turn it counter clockwise or toward you just 1 2 or 3 turns very slowly, you'll hear the fast idle come down but you don"t want the fast idle to low, listen to the engine very carefully, slow it down just a bit, it should still race though but not out of control. Of course for a full carb, adjustment the shop should handle that., but this info will help.