I have a 75 merc 650, 65 hp on a 20 ft pontoon. It has a 10.5x13 prop now.Top rpm is 4600. Manual specs, 5000-5400. Does a 11.5x10 or 12x10 sound reasonable? Thanks in advance
As a rule of thumb every inch of pitch will add or reduce WOT rpm by 200 increasing diameter will also reduce rpm as will the amount of cupping on the prop & the thickness of the blades etc etc as you can see there are many variables.I would try the 11.5 x 10.Good luck
