Trying to help a Bud of mine... He has an old school Schiada that has a naturally aspirated 454 CI motor that has a mild cam ( about 500 HP ) Anyway, he runs a mechanical fuel pump and due to the stock fuel delivery it takes about 30 to 40 seconds to fire after a 24 hour sit..somebody told him that he can run an electric primer/booster pump between the mechanical pump and the carb to prime fuel into the bowls to cut down on the cold cranking time to fire the motor. Anyone hear of this? I suppose you could run an electrical in-line pump with a manual switch but would this impede normal fuel flow between the mechanical to the electric to the carb? Thanks in advance!
No clue other than the configuration of the fuel lines could be sucking or sphyoning the fuel from the bowls. From the carb the lines go straight down (vertical) to a fuel/water separator then goes straight down again to the fuel pump
On Quadrajet carbs, there are plugs that are known to leak, causing various problems. The plugs are needed to seal the ends of drilled/machined passageways/circuits that supply fuel throughout the carburetor, and sometimes they just leak. They are located between the main body and the throttle plate, on the bottom of the main body.
There's some misleading internet information about fuel siphoning out of a Quadrajet carb through the fuel line. In actuality, it is possible, however it's nearly impossible. For this to happen, the screw in seat (of the needle and seat assembly) must be installed incorrectly/not screwed all the way down, the check valve in the fuel filter must fail, and the check valve in the fuel pump must fail... all at the same time. Otherwise, there's really no way for fuel to siphon out of the carburetor and back down the fuel line.
The article above should solve your issue. Probably gonna say "damn, I wish we figured this out 25 years ago" LOL