[jmk]

John, love that boat. Sounds like you've added some weight. The motors may need you to reduce your prop pitch. They are very solid but can fail within hundreds of hours if they cannot get to rated wide open throttle specification. Being over propped by only 100 RPM on the top end (reaching only 3700 RPM) is dangerous to the motor. Check your WOT RPMs. Would be true for any competing motor from Yanmar, Volvo, Cat, etc. Boatdiesel has volumes on this motor, best resource you will find.