I'm taking my 20hp out tom for a workout for the first time.I have like 30min on it with a quick ride and i darn near hit 30mph with the stock prop.I also have a 185lb boat.The rev limiter didn't hit but i bet i was real close.From what i understand they usually set it at like 200-300rpms above the max so if your hitting that with a 10pitch the 11 would be right at 6300 or a hair less.
Not to change the subject,but i just saw the 25/30hp come out like a week ago and it's a whole different engine then this but it comes standard with a 10pitch also,that's odd to me.But then i looked at some 25's 4strokes on youtube like the merc.I use to have that motor and it was a dog with a 12.5pitch prop,but this motor is also like 30lbs lighter then the merc,has a way a better gear ratio which should give it some great power to weight ratio.Plus it's also a 3cylinder which is even better,it will run smoother and should give it better power then the original 25.