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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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I have a 1984 mercury 150 that runs few minutes then dies. I

Customer Question

I have a 1984 mercury 150 that runs for a few minutes then dies. I rebuilt the fuel pump and it keeps doing the same thing. Any ideas why?
Submitted: 1 year ago.
Category: Boat
Expert:  Jeff G. replied 1 year ago.

Have you checked for fuel restrictions? If you squeeze the primer bulb will the engine keep running?

Does it start right back up or have to wait to start it?

Have you done any other troubleshooting?

Customer: replied 1 year ago.
if I squeeze the primer bulb it will stay running and I've checked everywhere but inside the carbs for restrictions
Customer: replied 1 year ago.
it will start right back up once primed
Expert:  Jeff G. replied 1 year ago.

We need to check for fuel restrictions. Easiest is to use a vacuum gauge between the tank and the fuel pump. If you don't have the gauge then try these things.

If you are using a gray fuel line the inner liner may have collapsed. Remove the primer bulb and look inside the hose. Is there a clear inner liner? Is it "loose"? If so replace the line with a new one.

Next go to the fuel tank where the line attaches. There is a hose barb there.

Remove the fuel line. Using two wrenches remove the fuel barb connector. There will be a small round ball inside. This is the anti-siphon valve. Replace the connector with a full flow through connector from an auto parts store or hardware. Either brass or aluminum, not steel.

Replace the fuel line and try the motor. Common to get a anti-siphon valve that is restricting the flow of fuel. Squeezing the primer bulb is strong enough to overcome it but the fuel pump isn't.

Try these and report what you find.

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