I have a 2009 188vx Ranger with a 150HP Yamaha HPDI. (I do not have a jackplate) I am only running 5100RPM and my top speed is 46MPH (gps). Everyone says this boat and setup should be mid 55-60MPH. The prop is a 21-M.
The motor is fine (just had it in for winterizing and such). Everyone I talk to (accept my ranger dealer) says I have the wrong prop. Any suggestions on what prop I should be spinning?