[99 Mariah 258]

Hello everybody.....
Took my boat fishing in the ocean a few weeks ago and after bobbing around a few hours I went to start it and it wouldn't start..3/4 tank of gas.... It would turn but seemed flooded. Got towed in and it started at home just fine but sputtered off after ten minutes so I left it alone. So I did a complete tune up plugs ,wires ,cap & rotor and the ignition coil. This weekend I took the boat out Sat & Sun and she ran great 6-8 hours.Starting fine with a lot more launch and power. I even fished in the ocean for a hour but didn't turn the boat off....Yesterday I take her fishing and it ran fine .....3/4 tank of gas. Drifted in the ocean a few hours and turned it on and she putters off in 1 min at idle and wouldn't start... Got towed in and it started at the house just fine...... Question is if anybody has had this issue. This boats driving me crazy

[Hudson River Steve]

I assume your 7.4 is fuel injected and not carburated. If it is the MPI, did you check that the fuel pump is operating correctly when she won't start? If you are close to the motor when the key is first turned to run (not start) you should be able to hear the fuel pump run for 2 seconds and then shut off. It sounds like you may have an intermittent fuel pump or fuel pump relay...or you could have another ground issue.