I have a reverse rotation 283, installed a new, 2bbl rochester GM rebuilt carb, now it is smoking and rough idle what to do
I have the air cleaner off and the choke is disconnected, the smoke is black and the inside of the exhaust pipe is black soot
mdk68gto, ase certified m tech
Favorite Answer
locate the idle mixture screws and turn them all th way in, then back them out 2.5 turns. make sure that the choke is free moving. the color of smoke would be helpful. if it is gray or black, then the fuel mixture is rich. if it has a blue tint, then you are burning oil.
bobweb
Make sure the carburetor choke and "choke pull-off" are working correctly from a cold start to a hot engine. The choke pull off is vacuum actuated and cracks open the top choke plate slightly (a calibrated amount) when you first start a cold engine. Then the choke should gradually be opened by the thermostatic bi-metallic coil on the intake manifold and also sometimes an electric element choke heater coil as well. Choke plate should be wide open (full open) after 10 minutes at normal ambient temperatures.
Remove the top cover of the air cleaner housing to watch what the choke plate does as your friend starts and heats up the engine for you. Watch out for your hands and possible backfires out the carburetor (don't look down into the carburetor).
Anonymous
Increase the air flow to the carb, running to rich means that the fuel to air mixture it to rich (in fuel).