quetion on prop spin out

[s delia]

My 2008 Legend has a 225 optimax. The boat gets over really fast and seems to perform really well, except in very rough water the moto wants to blow out when trying to get over. The prop is a 17 inch pitch. Can any one give me any ideas. Is this the prop?

 

[steelespike]

Re: quetion on prop spin out

Not a prop expert but I would say occasional ventilation is normal on a finely tuned setup.Be sure there isn't anything mounted on the boat that might disturb the flow of water past the motor.Be sure to trim in (down) when attempting to plane.Be sure the prop is in good shape.
If your prop is aluminum a change to stainless may improve the ventilation problem.Someone may be along with more specific info.
Might help to know the particular model boat and the max rpm and speed.

 

[Silvertip]

Re: quetion on prop spin out

What do you mean by "get over"?

 

[Texasmark]

Re: quetion on prop spin out

I was out the other day with the wind blowing really hard. The lake is small so the waves were small, but were highly wind driven.

I did my usual play thing and noticed for the first time that my engine picked up some air while trying to reach max mph, something it has never done in calmer waters I have operated in before. 1st time out with the wind like this.

I could get my wintertime 52 (50 gps) mph, but rpm's were up the couple hundred (to 5800-5900) that I'm up when I make tight turns and hammer down on it. I guess I was able to get my speed, even though I was ventilating because the boat was apparently riding on wave crests which reduced my hull drag and took less power to operate.

I know I'm susceptible to it (ventilating). The thing I like about this prop is that it won't blow out when it airs up (ventilates). It grabs a couple hundred and hangs on.

So, I'd assume yours is doing the same thing.

Mark

 

[Texasmark]

Re: quetion on prop spin out

Forgot something. When you say "get over" if you are talking about getting over the bow wake and planing, bow comes back down, I can cause ventilation also if I am trimmed too far out. Like if I were running at WOT maxed out and shut her down, then punched back out without changing trim position I can make my engine run up the usual 200 rpm which it will hold till I'm blasting along at a pretty good clip then it gets a bite of clean water and settles down.

So I'd suggest if that is what you mean, just tuck the trim in till you get it to stop. If you are really setup high, it may not stop and you'll have to use less throttle for your hole shot and give the boat time to gain momentum before you wind up the prop so tight; like get her up and over the hump with say 3/4 throttle and then hammer down on it.

Course you may need a hot-dog prop to stop it too, which would allow you to come out faster without ventilating.

Dhadley and Walleyhed are good at answering this type of question.

Mark