Quote Originally Posted by Phillipb71 View Post
The pump is in the tank but the relay and the fuse have been pulled. The pump in tank isn't running.
JMHO, an tank electric fuel pump exits the top of the tank and it usually doesn't work well pulling fuel through them up hill by a siphon type pump be it mechanical or electric. Siphon fed mechanical or electric pumps are usually sourced from the bottom of the tank allowing fuel stacked in the tank to aid in the siphon feed to the pump.

I'll bet Roger is correct, the in tank pump is running when the motor is operating, as this would explain the multiple carb and pump issues. Your pressure maybe lower while cranking if the tank pump is not on at that time, then once running I'd bet it's coming on and the pressure jumps up flooding it. Possibly someone hooked something up that was disconnected before.

Pinching a fuel line on the exit side of a pump will blow the seals/diaphragm unless it has a pressure bypass.

8psi is too much pressure for a carb. IMHO, no carb needs more than 5psi. If 5psi is not supplying enough fuel to the motor, your line size is undersized or restricted.

JMHO, I would use the in tank fuel pump with a bypass (return line) regulator near the carb set at no more than 5psi. And again, JMHO, the only thing wrong with Edelbrock carbs is people misunderstanding them, once adjusted and tuned correctly they will perform as well as any other...