15HP Merc outboard in a bad mood

[wgoodhoofd]

We have a 2001 15HP Mercury 2-stroke that seems to be getting mad at us, and maybe some of the guys here have a good diagnosis.

Gas line connects to engine, primer bulb squeezed, motor starts up. After a short time, the engine dies, and will not start again. When I remove the gas line, there is a pressure release, suggesting that gas cannot go from the tank to the carb efficiently. After wiggling the connector around at the engine, primer bulb becomes soft again, then hardens up properly and the engine runs again.

Once the engine is started it runs fine, but has a few hiccups here and there. I don't feel entirely safe in it.

My thought all along has been that the valve on the motor at the fuel intake is damage/blocked/deformed. I think this because the engine runs properly with gas in the carb, but once that burns out, there is no fuel available to replace it. My dad replaced the gas tank and hose at the suggestion of the marina, before committing to any larger repairs. Unfortunately this did not fix it.

Do you think I'm correct in this diagnosis? I'd like to get it fixed before the end of the season.

 

[CharlieB]

Re: 15HP Merc outboard in a bad mood

Sounds as if you are running out of fuel in the carb.

It may be time to rebuild/replace your fuel pump.

Depending on which model year, if the fuel pump is before or part of the carb, if before, disconnect the fuel line and direct towards any suitable container, turn the engine over as iff to start, observe the fuel flow. You are hoping to see a decent volume of fuel pulsing like a heartbeat. If weak or no stream rebuild/replace pump.

Later models with the pump cast/part of the carb, go ahead and order the pump kit(s), they are not that much.