WOT rpm low.

[ASmith11183]

So I just bought a DF 9.9hp for my jon boat. Total weight with boat, batteries, myself and gear is around 800lbs or so. Started with 11 pitch prop and WOT was only around 3100. Moved down to 9 pitch and got to 4200. That's still outside the 4500 - 5500 WOT rpm. Should I go down in pitch more? Boat is a Tracker Grizzly 1448.

Also, how difficult is it to squeeze a little more out of this motor? I think the 9.9 and 15 are same motor, just the 9.9 restricted. I noticed in parts diagram the carbs are the same, just different jets. What else need to be changed?

[boats.net]

Yes need to drop to at least a 7 pitch. Don't know about increasing HP, I don't alter engine horsepower.