I have a 1975 evinrude 9.9. After a complete overhaul, a 15hp carb, & Boysen double reeds, it makes around 18hp. It's mounted on my 13'6" alum. Jon. With me, the 12gal fuel tank, & the troller & batt, I'm gettin 21.9 mph on the gps. I've heard I should be gettin more, though. I've done moderate...