Originally Posted by cruiser
I did a lot of work on 30ft. plus chris crafts years ago with the same problems. If the shaft is straight, prop is straight and balanced and the key slot and key way are cut to proper depth. By this i mean put the prop on without the key in place and mark with a black marker, then remove the prop, install the key and replace the prop. It should go back on to the mark. If it does not you have to mark with hi-spot blue and scrape it in. If the prop does not go on to the same location, under load you can get a vibration from what we used to call Prop Wiggle.
Interesting write up - I'll have to check this out...