I have a 22 foot Sweetwater pontoon with a 2007 90 horse evinrude e-tech. It has a 13.5 x 15 aluminum prop and runs maybe 20-21 mph (as per the gps). Max rpm is about 4700-4800. I'd like to get a little more speed by changing the prop. I have to check my prop p/n to see whether it is a cupped or...
