4.3 Mercruiser won't run, sometimes

[JK Turtle]

I've been looking around but can't find an answer. I took my boat ('10 Tahoe Q5) out on Thursday, but wouldn't not start when I launched it. I took it out last week and had no problems with it. It sounded the same as it usually does when it cranks, just would not run. I checked the safety kill switch (that has gotten me a few times), but it was in place. And usually if it is the kill switch, the engine will run, but just die right after it starts. So I pulled the boat out of the water, was packing up to go home and figured I would test it again one more time, and it started up. It ran for a couple of seconds, I killed it, launched it again, it started, it ran for about 3 minutes, died, and wouldn't start again. I brought it home, the next morning I went to look at it, hooked it up to the hose, and it started right up. And that is where I am at now.

Is there any other safety switches I am missing that it might just have a loose connection and the bumps in the road is moving it around? Or what? I am kind of lost right now, and just figured I would get some other peoples opinion. Thanks.

 

[alldodge]

Need to get to the basics. It could be the kill switch not making connection all the time, or something else. When it doesn't start you need to be able to check voltages. My guess would be it is electrical issue and not fuel.