1994 40hp 4cyl Mercury. What would be considered minimum fuel pressure? I can't find it listed in the service manual. I can pump the bulb and get it up to 10psi., but running, it seems to be only 1 or 2psi.
Hook up your fuel vacuum gauge just befor the fuel pump. First check for fuel restrictions while running no more than 4" of mercury, secondly kink the line right after the primer bulb and watch the guage. If your vacuum raises to about 6+ inches of mercury your fuel pressure should be considered fine.
Serial#?Some 3/4 cyl have electric pumps and some have 2 pumps.
The squeezie is used to overcome a low pressure pump.
Most outboards don't need a lot of pressure to keep it running.The ball primes the system.
The pump doesn't have enough pull to prime the motor.You would wear out the starter trying to get it started without the ball.
1-2# is all you need.
It would cost $15 to rebuild the pump.J
