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Ask Dominick Your Own Question
Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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Can someone tell me if my fuel pump on a '94 mercury marine

Customer Question

Can someone tell me if my fuel pump on a `94 mercury marine 4.3l engine has a check valve located in the pump itself to prevent back flow while it is sitting idle?
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

The fuel pump does not have a check valve. But the boat has a check valve at the fuel tank where the fuel supply line connects. This is called an anti siphon valve.

What seems to be your issue?

Customer: replied 1 year ago.
Fuel all drains back out of the carb. after sitting over night or for a few hours .course then pump don`t run long enough to prim the carb again to start the engine.
Expert:  Tan replied 1 year ago.

Ok remove the fuel supply line at the fuel tank and unscrew the barbed fitting the hose connected to. Look inside the fitting you should see a check ball. The valve should only allow fuel to flow one way.

Customer: replied 1 year ago.
Ty Tan I`m going out now and try that. Crossing my fingers hoping your right. lol
Expert:  Tan replied 1 year ago.

OK. Let me know what you find.