Cutless bearing

Posted By: Ray Henry, Nimble Kodiak Yawl, "Seaweed", NC
Date: 2/1/08 4:24p.m.

Report: outside forum guidelines

In Response To: My mechanic says an alignment can take anywhere from 3 to 8 hours, (Craig Hershoff)

My strut is perfectly straight. When I got the boat, my cutless bearing was worn at the bottom side of circumference on the aft end, and the top side of the circumference on the forward end. There wasn't much play (maybe 1/16" or so). Since I was there, I decided to replace it. The old one was a chore to get out, even with the shaft pulled. Naturally, the set screws were frozen in place, naturally I stripped the heads getting them out...... I drilled and tapped some new holes and put in a new bearing. The only bearing(s) I could find were shorter than the length of the strut (the old one was, too). I left the "gap" at the forward end, as the old one was, so that it would act as a funnel for water to get pushed into the bearing. Anyway, what I found was that my strut didn't line up with the shaft log hole glassed through the hull. This is why the bearing wore at the top on one end and the bottom on the other. Even when not hooked to the engine, the shaft is ever so slightly bent with respect to the line between the bearing and the hull entry. With any amount of bearing wear at all, it fixes itself, though. I will re-grind the entry hole of the shaft log at some point, I guess..... I have vibration at low rpms, but I think that is due mostly to the engine vibration and Yanmar's notoriously "mushy" mounts. If your cutless bearing/shaft has a lot of play (but you said their wasn't......), the shaft will tend to flop around inside it and make noise/vibrations. As you increase RPM's the shaft will centrifically (sp?) center itself and it will smooth out. Your reverse-gear thrust may be causing it to flop around if it there is a lot of play (but you said their wasn't......) I doubt this helped you any, but I just felt like typing.....