Re: 3 blade to 4 blade
Hate to say it, But your boat is running good with the 10 pitch and yes I have seen the same drop in RPMs with putting on a 11 pitch props while testing pontoons just like your set up. Try playing with this prop selector with your boat specs. But 18 mph [on the speedo gauge] at 5800-6000
with a little trim is right where you want/Need too be at with your set up for over all use.
http://appcenter.mercurymarine.com/propSelector/home.do
Do you have the big foot set up?
The 4 blade would help if your set up had a lot of cavitation going on but you would lose some top end performance over all in most cases, But if you wanted to or needed to use a 4 blade, Then you would need to go down in pitch by around 1 pitch some times 2, If they even make them for your set up from merc, I Can't remember right of the top with out looking it up.
:redface:
.
Now Mercury does make a cupped prop to work better for most pontoons. And If you look at the part number on the prop you would know if it is cupped or not, Because it would have a "C" in the part number for cupped. The cupped prop would be a 50/50 chance for a better performance, Or better handling if you had a lot of cavitation going on Then you would want to try using a cupped prop also to help with that. But you would not know till you tried it all out to be sure.
