1999 Tige 2200i/mercruiser problem

[stecz]

This weekend, I was using my boat and had a strange issue. At lunch time, I would anchor the boat and leave it for an hour or hour and a half or so. When I restarted it, it would start fine, idle ok, but a little rough, but when you put it in gear, it would pop, and not rev, etc. If I took it out of gear and moved the throttle back and forth, it would eventually clear up and run perfect.

It has never done this on hot start or a dead cold start and it's never done this before.

This is a mercruiser 5.7l MPI (315 hp) motor. It has less than 200 hours on it and was just serviced less than 20 hours ago (get it ready for the season).

I haven't pulled the spark plugs to look at them, but it really sounds like one of the spark plugs is fouled or something.

I was also going to run some techron through it...