bad to run overpropped? And which prop is right for me?

[txhorns0508]

I just got a 250 yamaha 2 stroke put on my mako 231 and have been trying out a few different props as I could find them. I ran a 17p and it was not enough and the boat was really slow. Right now I am running a 23p and the boat is really fast and pretty good out of the hole, but it won't get over 4300 rpm. Will running my boat with this prop hurt the motor if I stay at more like 3600 rpm? I'd kind of just like to use the boat this weekend even though I won't have the right prop in time.

Also, does anybody know what the right propeller for me is? I'm thinking a 19p - should I go with a 15" or 15.5"? I know nothing about props and want to make sure I get the right one since they are so expensive, so I really appreciate the help.

 

[jestor68]

Re: bad to run overpropped? And which prop is right for me?

Yes you are "over propped". Yes, it is bad to run under the manufacturers recommended full throttle rpm range.

The 19" pitch sounds about right to pick up about 800 rpm, putting you right in the middle of your recommended rpm range (4500-5500).

Your motor will thank you.

 

[Georgesalmon]

Re: bad to run overpropped? And which prop is right for me?

You are pretty close to the low end of the rec WOT rpm. Don't think running one weekend is gonna wreck your motor. But I wouldn't do it forever. IMHO

 

[steelespike]

Re: bad to run overpropped? And which prop is right for me?

I agree but keep in mind if your over propped, your over propped through your whole rpm range.
Is the 4300 with your typical load? If you will be adding a load of people and gear you may want to consider the 17
and watch your room stays within range.
Should be ok for a weekend.Are these 2 props basically the same but for the pitch another words both 3 blade aluminum
or 3 blade stainless?