Have recently purchased humber 6.5 with yamaha 150 4 stroke. Both about 1-2 years old engine has only 80 hours on it. Prop is alumimium and has a tiny ding on one blade where previous owner may have clipped something.
At between 2500 -3000 revs the boat has a vibration in it and this disappears above that rev range. Is this vibration normal in this set up - would it be caused by the prop or is there a more sinister reason for it.
I intend to swap prop with one off another boat to see if it makes any difference . Anyone got any similar problems with the same set up.