1996 Yamaha C40PLRU Fuel Problems

[Altro Cat]

Bought boat with this motor on it last winter. It runs fine and reaches WOT but almost every time I shut the motor off I have to pump the fuel bubble until it is rock hard to get it to open up again. If I start it back without pumping the bubble it will start but when I put it in gear and try to accelerate the fuel level in the fuel filter drops and the motor dies. If I pump the bubble up each time it runs perfect, I can slow down to idle and then accelerate again with no trouble but if I shut the motor off I have to pump the bubble up again.

Any ideas??

PS - I have changed all fuel lines, fuel bubble twice, cleaned carbs twice, new fuel tank, cleaned screen in fuel filter, new fuel pump(not rebuild), all fuel fittings are new.

[boats.net]

If you are tilting engine up when shut off then may have to reprime before starting, check compression, Resync and adjust carbs. Check fuel pump.