I have a 1978 El Camino w/ 305 2 barrel carb.
The car has been setting up for a long time, it runs great.

The problem is after the car sets for a day or so the fuel bowl in the carb. drains somehow? The carb. has been rebuilt recently.

Can the fuel pump cause a suction and pull the fuel out of the fuel bowl in the carb. if the pumps diaphram is bad?

HELP..

Its a QuadraJet! What else do you expect.......? No just kidding that is a very common issue. The deal is that the fuel bowel has a leak, turn the carb upside down and look dead center. You'll see the Jet Housings, those housings crack on almost every QuadraJet ever made. Over Night the fuel leaks out into the intake manafold.

Use an Epoxy to seal it up. Clean it really well, really well!!!!! then use some epoxy, I used JB Weld but you can use whatever, mix it completely cover the recess and let it dry. Put it back on and it will not have that problem. Most of the rebuild kits for the Q-Jets have these instructions in them. And probably explain it better than I do.

Good Luck.