I let my truck sit for too long with old gas in the carburator and naturally it turned to varnish. The linkage in the carburator would barely move when activated by hand (the throtle pedal wouldn't come close to moving it). I took the carburator apart and cleaned it up and re-assembled it with a new gasket kit (not a rebuild kit). I put the carburator back on the motor and now when I start the motor the rpm's jump to about 2500-3000.

I also installed a Gear drive inplace of the timing chain and thought I may have altered something in the timing that may cauese this problem. When I installed the gear drive I used the 0 degree cam bushing that came with the kit thinking this would be closest to stock timing on a 350 chevy (4 degrees before tdc).

Anybody know where I screwed up?



If this is a repost, please direct me to the thread that has already covered this problem. I couldn't find one. Maybe I didn't look hard enough.

check for a vacuum leak at the carb or manifold. on open vac port will usually cause the idle to race like you describe.

with the engine off, look down though top of carb, verify that the throttle plates are closing fully. could be build-up on plates/base plate, or linkage could be bound....
idk that a vacuum leak would get r.p.m. to 3k.

Thanks for the help.

If I can find it, I have the old Quadrajunk carburator that was on the motor when I bought the truck. I'll stick it on there and see what happens. It was running when that carb was on there, not very well, but it ran.

X2 on the vacuum leak and X2 on the throttle plate not being fully closed. Could also be a cold start valve or assist if your carb has one. I know my Edelbrock has one and is adjustable. Lean will raise the rpm and fat would cause it to come down.