Originally Posted by Celestialsailor
does not lubricate the bearing by it's loosness. There are linear serations along the length of the cutless bearing that does this. A 1/16 or .062" play is excessive. When new, it should be a light slip fit. Either the bearing is worn out or the shaft is worn in the cutless area.
A few facts are needed here I think, having run a business supplying bearings for a number of years.
Bearings for shafts (or rudders) that are emmersed in water or fed with water are water lubricated. any bearing that is lubricated by a liquid (or grease) needs a small clearance to allow a film of that lubricant to establish itself as the shaft spins.
The water ways or oil
ways in an oil
bearing are to allow a flow of liquid to aid cooling
. A water film will support a surprising amount of pressure when the surface is moving, think of it like aqua planing when you hit a shallow puddle at speed, slick tyres and you'll aqua plane earlier, same with bearings fewer water ways and the shaft will float on a layer of water sooner.
So sorry to disagree with you celestial, but I think it's important for people to know that you do need a running clearance from new to allow this film to lubricate the bearing.