New boat owner this summer... 98 sea ray 175 with 3 ltr merc 135hr. Supper clean boat, motor purr's but....only getting 36knts at 4400rpm. I was told the boat should go 40 to 42. Hull could use a cleaning and wax. Current prop, merc 14.5 x 19. <br />Q. How accurate is rpm gage on a boat.<br...
