Warranty issue?
OK, so that's the first thing that came to mind... Funny thing about harmonics, it could be almost anything...but they usually stay at one rpm or at a multiple, they don'y generally move unless something changes. I guess one way to know if it is the tranny is to take the engine out of gear and rev it up. If the noise is still present, it probably isn't the tranny. If it is, could be the tranny, the length of the prop shaft, the prop, the balance / alignment of the shaft, etc.... If the noise is still present in neutral, it could even be another part of the boat. For example (not saying this is your issue) - my boat has a hatch cover that vibrates at certain engine speeds. Best of luck tracking the noise down. Bob
