How much play is normal ?

[joe]

I have been having a little vibration on my boat since I bought it new 3.5 years ago. I have a folding 2 blade prop which I thought was producing this irritating problem. This spring I plan on changing my prop over to pyi 3bladed maxprop. What seems to worry me is today I was down at the boat yard and was comparing shaft play with other boats, most boats did not seem to have any where mine does. My question is is it normal to have a little give within the cutlass bearing allowing the shaft to move and do you think this is the source of my vibration. I have aproximately 600 hours on my yanmar3jh2e engine, also the vibration I get is absent under 1800rps then I have a very noticeable shaking for about300 rpms then as I accelerate with engine rpms the vibrating diminishes, although I still have mild vibration.

 

[kevin]

bearing

Hello Joe, In my opinion 1/8th of an inch play is ok. If the system were apart at this time I would however replace it. If you took the time now you won’t in the near future. One thing to remember is that once the bearing loosens up the destruction of it accelerates. The 600 hundred hours to this point may only take 100 hours to produce another 1/8th inch. Hope this helps. Kevin