Who Here Is The Resident Carburetor Tech?

[atikovi]

My ’79 Chevy Santana camper van will sometimes stall when you come to a stop when it’s warmed up. I can restart it and put it in gear and it can be fine until a minute later it may happen again. It’s a 350 engine with 63,000 miles and the carb is a new (factory rebuilt I assume) Rochester Q-Jet. It also has new plugs, wires, cap rotor, etc. The timing is at 6 before, spec is 8 but that’s close enough.

 

I set the throttle stop screw to make it idle at 1500 in park so it won’t stall in gear but that’s not good, and even then it's not guaranteed not to stall. I adjusted the mixture screws for the highest idle, about 3-4 turns out, but the engine doesn’t feel as smooth as it should be. It is smooth off idle though. A vacuum gauge shows a steady reading. It was at about 12-13, then after playing with the mixture screws I have it around 15.

 

Any ideas why it stalls and won’t idle very smooth unless the speed is turned up? Air leaks maybe? I sprayed a quick shot of starting fluid at the base of the carburetor and the engine speeds up a bit. The mounting screws are tight though.

[ChevyTech77]

Sounds like you have a vacuum leak. Use carb clean instead of ether though, better results.

 

If not, you might be low on fuel pressure.

[old dog]

i would defently check the base gasket and all vacume hoses ,maybe check the float level if all else fail's it could be running the gas away from the jets when you hit the brakes

Sounds like you have a vacuum leak. Use carb clean instead of ether though, better results.

 

If not, you might be low on fuel pressure.