The Stovebolt Site Forums The Shop Area Engine Shop 58 Apache 3200--vacuum advance???

My truck has a 283/4speed with a Rochester 2-barrel carb. A few months ago I had the carb rebuilt by a shop in Sacramento that has a good reputation. With a little choke and fast idle it runs great. With no choke it balks when I try to accelerate. At first I thought a bad rebuild job, but it acts the same with the vacuum advance disconnected. I am leaning toward a vac adv problem. What do you guys think?

Lee Beckman

What you describe can be a vacuum leak, either in the carb, under the carb or somewhere else on the intake manifold or a ruptured diaphragm in the vacuum chamber. Or it can be a little trash in the main metering jet. I would eliminate the simplest first. Disconnect the vacuum line and plug it. Same for the wipers if you have vacuum wipers. How did it run before you had the carb rebuilt.

Before the carb rebuild it did not seem to balk at low end acceleration, but the butterfly valve on the carb was frozen at about 1/2 choke. When I removed the carb it had a solid gasket with only the openings for the 2 barrels. The carb factory gave me one that had some slots that looked like heat exchange stuff--could that be the problem?
Lee

Do you still have the old gasket? If so, try using it with some Permatex. Its going to be a trial and error thing, and I always try the easiest first.

Trial and error---absolutely. After trying a lot of things, eventually it turned out to be a defective old fuel filter and a carb that needed some adjustment. Now all appears to be good. Thanks

Lee