Slow Engine RPM

[Greg Johnston]

I have a Yanmar 13HP engine that is only turning 2500 RPM's at full throttle. I do have a Max-Prop but don't think it's out of adjustment because the engine would turn around 3000 RPM's or so last year. It seems like everything is a strain on the engine, ie. going against waves. Does anyone have any suggestions? Thanks.

 

[John McDaris]

slow rpms

I have a freind with the the same boat hunter 31, i also have the same boat and motor, he was having that problem I was not, he cleaned the bottom and prop and the problem went away. I take mine out every year, he had not taken his out in almost two seasons. The diver said he had all kinds of build up on the prop and bottom.

 

[Eddy Johnsen]

Throttle Cable

Greg,Sounds like you might have the same problem I experienced with my Hunter 30 last year. Turned out that previous owner had placed a tension clamp on the throttle cable to alleviate "slip" in the cable. I merely had to tighten the clamp and my normal rpm was magically restored. If you don't already have one on yours, you may want to consider this cheap & effective solution.

 

[Chris B]

Check this out

You didn't mention if the problem occured under load only. If so, I had the same problem. I could get full rpm in neutral but low rpm's under load. It turned out to be a slight leak in the a fuel line fitting. Make sure every thing is tight. Good luck.