Originally Posted by kyle86
This problem has been anyoing me for a while. Holley 4160, 80508 750cfm vacuum secondaries.
It is intermittent. If i crank the car up, I usually have air in the acc pump. I pump the gas a few times and then it's clear and works fine. Same happens if I'm cruisng for a while and then pull over, if I pump the gas, it stumbles, but once the air is out, it works great from there on. It's like air slowly gets in it when it's not in use.
I've already changed the acc pump gasket and umbrella valve. Not sure what it could be now.
The check valve seat under the squirter has to be in good condition. If you have a used check of the same type your carb uses, you can use it to carefully reform the seat itself.
You place the check down into the hole, then using a long, thin, flat-ended punch, gently
tap the check w/a small
hammer. This will remove any raised edges or whatnot that may be causing the check to not seat tightly.
For the bottom check, if you have the rubber umbrella, be sure that it is still very pliable and the sealing surfaces on the carb as well as the umbrella are smooth and defect-free.
If it has the older "ball and bail" style check, use the same procedure as for the under nozzle check to reseat the ball.
Removing and replacing the bail is no fun, and must be done very carefully so as to maintain the slight bend in the bail. It's best to re-peen the metal to secure it back into place. Only do this if it's necessary.