low power/high rpm

[mgaray]

I have a 1988 18' Cobia bowrider with a 130hp Merc that has an Alpha1 outdrive. Last season I had the prop replaced and the engine tuned up. As the season progressed I found my speed decreasing and my engine RPMs increasing to the point where<br />full throttle should be running 4600 RPMs, I now get to half throttle and it is close to 6000 RPMs<br />Any ideas?

 

[chuckz]

Re: low power/high rpm

Power is not getting to the prop, something is slipping. I would start by checking for a spun hub in the prop and work backwards from there. It may be as simple as finding fishing line tangle around the porp shaft when you pull the prop.

 

[JB]

Re: low power/high rpm

I/O topic.

 

[trog100]

Re: low power/high rpm

thats assuming your prop is down in the water where it should be.. and cavitation isnt taking place..<br /><br />trog100

 

[waterone1@aol.com]

Re: low power/high rpm

I have to agree with the above posts. Sure sounds like a prop hub spinning or a drive that is too far out of the water.