another motor hight question

[basszzilla]

I just installed a 1989 mariner 90 horse on my 1983 skeeter 15 ft. I also have one of those dolefin. <spelling? devices on it. It has a wonderful hole shot. The problem is at about 30 mph/3500rpm it seems to over rev, at WOT,like the prop has come out of the water. I sat the motor at the highest setting to achieve alignment with the anti-cavitation plate and lowest point of the hull. I have had the prop tested for slippage and it is ok. What am I doing wrong here.

 

[DJ]

Re: another motor hight question

basszzilla,<br /><br />Take the Doel Fin off and retest.<br /><br />They can sometimes trap air under them.

 

[Jdeagro]

Re: another motor hight question

What is the attitude of the boat when you are running at 30 MPH and the motor is at 0 trim? Is it running bow down?

 

[Old Jarhead]

Re: another motor hight question

If you're only turning 3500 RPM @ WOT then I believe the problem is the prop (pitch/diameter) size.<br /><br />Height sounds right but you could be trimed out too much. Still 3500 RPM @ WOT doesn't cut it...

 

[basszzilla]

Re: another motor hight question

hey guys, here is more info. when the motor starts to over-rev I will back off throttle a little and it seems to pick back up I can get it up to about 42mph/5000 rpm. it just seems to do it when I hit it full throttle.

 

[LubeDude]

Re: another motor hight question

Are you running a stainless prop, I think you need more cup also.

 

[basszzilla]

Re: another motor hight question

stainless yes. seems to plane out just right and lays down real quick, just when I nail it at those speeds. I,m glad you guys havn't ask me for prop specs yet, I think I will have that info handy before I next login. thanks for all your help.