HiYa, all, I just had a fresh rebuild on my Holley 600 (9834-3). While TRYING to set the idle mixture screws,(only two in the front) the passenger side works fine. When I screw it in, the motor will starve & when backed out , it will run. The problem is the drivers side screw. It will not cause ANY effect at all. If I screw it in all the way, the motor still runs, telling me something is jazzed up! Also, something bizarre! When the engine is warmed up and running, I noticed hardly ANY heat from the drivers side valve cover & exhaust manifold as opposed to the passenger side being HOT! I then went to the exhaust pipes and noticed white smoke vapor is only coming out of the passenger side telling me the whole drivers side of the engine is not getting ANY or very little fuel to combust. This makes sense since the drivers side of the motor is not as hot as the passengers side. I checked the throttle blades and they are not open too far to override the idle circuit and I took the idle/air screws out and shot carb cleaner with the red plastic tube into the holes and the carb cleaner shot out of the hole above the venturi as they should, so no blockage there. Is only 1/2 of the carb functioning? Could something be blocking fuel that is not able to flow into the idle mixture chamber? If I had another carb to switch out I would but not at this time. Has anyone ever had this happen? Thanks in advance!

with a Holley 600 carb I'd guess you are running a dual plane intake, in which case half the carb is feed two cylinders on each side of the engine.

The only time I ever saw a complete side of a V8 not "running" was when the plugs were so carboned up on one side that they were fouled out. Bad intake gasket seal n that case.

Sounds like something went awry in the carb rebuild and you have other issues affecting the one side of the engine.

Hopefully the rebuild was done properly, and the proper gaskets used in regards to the metering block where the idle mixture screws are located, the fact that the idle rags/stalls out when you screw in the (one working) idle screw shows the Power Valve is working, I'd suspect you might have some debri in some of the metering block passages, I'd remove both idle mixture screws, and blast some compressed air into each screwhole, the passage will be clear when you can feel the compressed air coming from the air bleeds located in the carb's primary side/half, in the throat...


here's a pic to help you locate the air bleeds, they are the 4 small holes located near the base of the choke airhorn, 2 on each side of the primary/front half of the carb, you should have a clean passage from ONE air bleed on each side, to the idle mixture screw for each side of the carb...


Mike