2002 Mercruiser 4.3 Stalls after start

[Phil Chieco]

Hello, I went to start the boat this spring and it starts and idols for about 30 secs to a minute and stalls. When I give it gas it revs but then stalls like its starving fuel. I have checked the fuel separator and there was no water. Fuel is fresh and winterized with Stabil. When I pumped the accelerator I noticed it was spraying in the carbs. So it looks like the accelerator pump is fine. I also propped open the choke and started it and still had the same issue. I also tried going a full turn left and right with the fuel mixer but that did not help. I am wondering if it is the low pressure electric fuel pump maybe that is going bad. Is there a way to check that? Any thoughts would be appreciated. Thank you Phil

 

[Stephen]

Put the carb adjustment back where it was. Do not prop open the choke butterfly. It's there for a reason. It should be closed when starting and then the choke pull-off will open it slightly. If electric, do not leave the ignition on before starting because the heater will open the butterfly more, causing it to starve for fuel. Just give advance the throttle before starting and allow the linkage to close the butterfly. If it doesn't close, check for free movement of the butterfly and linkage. You may just have crap gas in the lines and need it burn off to draw fresh gas from the tank.

 

[Phil Chieco]

Thanks for your comments. I did figure out the issue. The contact points at the oil sending unit needed to be cleaned as they were shutting down the electric fuel pump. Once cleaned the engine rain fine.

 

[Stephen]

Good deal. I had to replace mine one time. Not a cheap part and I regret not spending more time diagnosing the issue. I read once that they sometimes appear to fail but come back to life if you strike it smartly.