1997 Four Winns 4.3L Stalling

I have a 1997 Four Winns Horizon with a 4.3L Volvo Penta. It periodically stalls -- sometimes going slow -- sometimes going fast. It is not getting gas. I have replaced the electronic fuel pump and the anti-siphon valve in the fuel tank. I have taken it to the marina a couple times -- but this is an irratic problem. Finally they installed an inline squeeeze pump bulb in the fuel line from the fuel tank to the carb. When it stalls I punp that bulb and it is fine. Not ideal but it works.

What could be causing this? Could it be a vent problem with the fuel tank? Any ideas appreciated.

Thanks,
Tom

 

Stalling

if it runs when you pump the bulb, it is a sign the fuel isn't making it to the engine. Check for air leaks. Loose clamps, pin hole leak in a fuel line. It sounds like it is sucking air and loosing it's prime. Because it is intermittant it could be in the tank. After the fuel gets to a certain level it uncovers a hole and air is sucked instead of fuel. But check the whole system. Also check the routing of the fuel line. If it gets too hot, fuel may vaporize in the line. Result is called a vapor lock, but it is basically the same thing. The fuel pump will not pump air/vapor, must have a liquid to pump.