4.3L Volvo Penta in '97 Horizon QX fuel line prime loss

[Channel6]

Fuel System questions on 1997 Horizon QX 4.3L. Great little boat until the fuel line loses prime. It sounds like many have been up this river before. The common thought seems to be vapor lock as the cause, but by across the solenoid connection for the fuel pump and noting that the fuel line is pretty empty, I think the problem might be fuel being pulled back into the fuel tank? I do get the boat to recover when I do this but I should have to. My thought is to check the fuel tank vent, but there does not seem to be one. Is the '97 Horizon 4.3 set up to vent from the gas cap? -Thanks, iBoaters.

 

[alldodge]

Could use some clarification with your statements

Is the motor a carb, TBI or MPI?

The common thought seems to be vapor lock as the cause

Vapor lock happens from heat soak on the fuel injected motor, after it is shut down and given enough time for the fuel to boil

by across the solenoid connection for the fuel pump and noting that the fuel line is pretty empty, I think the problem might be fuel being pulled back into the fuel tank?

I think your saying when the fuel pump solenoid/relay is jumped the fuel pump will run but you get no fuel out of the pump?

 

[QBhoy]

There is normally a non return ball valve in the fuel supply line. Check and see if it’s there and if it’s failing with crud sticking it open.