135-hp MerCruiser 3.0L sound like its missing at idle.

[Mike Yelland]

I have a bayliner with a 135-hp MerCruiser 3.0L. Last weekend I was boating and everything was fine. I put the boat in neutral, then after about 4 min. I put it back in gear it started missing. If I make the motor go above 2500 ? 3000 rpms it runs fine. What should I look for?

Mike

 

[Don S]

Re: 135-hp MerCruiser 3.0L sound like its missing at idle.

When was the last time it had a full tuneup? Including a compression check? If you don't know, then it's probably time for both.
Start by pulling the spark plugs and reading them. What do they look like? That can tell you a lot about the condition of the engine.