What prop is everyone running on there 30hp ?

[Philippe12]

I have a 09 mercury seapro 25hp with removed restrictor > 30hp. I have a 1990 princecraft resorter flat bottom 14" boat with simple steering console, light wood floor. I'm doing 30-32 mph with 2 people, I get on plane in <10secs. The motor has 1.92 gearing and is running a 10X13 prop. Wondering how much I can gain going to a 15pitch prop, seems like the way it runs now I could go with more prop pitch, it screams pretty good at WOT and it will plane even with 4-5 poeple in the boat or camping gear higher than the sides with a slower top end of course but it will ALWAYS plane but i'm willing to give some of that up.

 

[steelespike]

Re: What prop is everyone running on there 30hp ?

The best way to change props is with a tach.To tell better what you need and to tell better your results. Something like a tinytach will work.
In the mean time check the height.The antivent plate(just above the prop) should be about even with the bottom of the boat and could be up to an inch higher.

 

[Philippe12]

Re: What prop is everyone running on there 30hp ?

I have already put a spacer on the transom to lift the motor so the plate is even with the bottom of the boat, and perfectly level to it also. I will try a 15" prop and see what it does on gps.

 

[steelespike]

Re: What prop is everyone running on there 30hp ?

Some boats may require more up trim. The 15 will slow your hole shot and may make load carrying a drag.The motor is rated for 6,000 which I'm sure sounds high at speed.
I think the 15 could knock 500 rpm of that.It probably will add some speed once you get there.
The 15" is the biggest prop listed on iboats.