cavitation problem

[cjlake]

I have a 1979 21 ft mako, with 2 115 Johnson OB. At time's the right engine will cavitate and the RPMs jump way up. I changed the prop but have the same problem. The past owner said he could not find the problem either.
Both engins have right hand props. They also seem to be engaging all the way.

 

[JB]

Re: cavitation problem

I suspect that your engine is mounted too high or being trimmed too far out(up).

I also think you are getting ventilation, rather than cavitation.