We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re exploring possible causes for leak downs in Quadrajet carburetors.
S.O. • Round O, SC
Q: I have seen numerous Rochester Quadrajet carburetors that have a leak down problem when the car sits idle for a day or more. My question is, how is the gas getting out of the float bowl, and how do you fix it? I have this problem with the Q-Jets on my 1972 Electra and 1986 Chevy pickup.
A: There are two things that can cause a Quadrajet to leak. First, check the two plugs in the bottom of the float bowl. These have a habit of coming loose, which will let fuel in the float bowl drain into the intake manifold.
The second thing is the fuel inlet. Since it sits at the bottom of the float bowl, fuel has a tendency to drain back through the fuel system to the fuel tank.