I just purchased 1996 1650 lund with a 1999 Honda 75 horse power outboard.It came with two propellers 17pitch and a 15 pitch. Max speed with the 17 was 37 mph and 35 mph with the 15. The tach was reading 4800 rpms with both propellers.<br />I think the tach is bad. I pulled the motor out of the...