Mercruiser 5.0 intermittent start issue

[Triumph]

Hi, I’m new here, have a start issue. Recently boat would start then stall. Replaced the oil pressure sensor switch which solved the problem but now the issue has reoccurred. The boat is carbureted and the re is fuel getting to the carb. Boat runs when gas poured directly into the carb. Fuel water separator changed. Thanks

[mmwjr]

Welcome aboard!

You didn’t state the year but based on what you said it must be a 1998 or nearer as it has an electric fuel pump. Try jumping across the two wires of the oil pressure switch temporarily to see if the boat will run. If this works the switch is faulty. If this doesn’t work try disconnecting the fuel line into the carb and crank the engine to see if fuel comes out. If no the pump is bad. Note use a catch can to collect the gas.

[Triumph]

Thanks! Did both. Have gas pumping to the carb and bridged the oil sensor. This seems to be a new issue after replacing the faulty oil sensor. All I can think is the float bowl may get stuck closed and the boat quits when the float drains. Next I’ll pull the carb and rebuild and clean it. The boat eventually runs usually after I disconnect the fuel line to check for gas flow. I also give the carb a wack with a wrench! I wonder if I get a weird air lock in the carb. Once the boat gets going it runs great

[mmwjr]

Sounds like the float/needle valve is getting stuck. I would rebuild the carb.

[Triumph]

That’s definitely the next maintenance item. Thanks for the advice