So I took my boat in to have the annual maintenance conducted on my outboard (65hp yamaha). Today I recived the dreaded call that my shaft is bent. It was bent bad enough that there was "some difficulty" pulling the impeller off, but not so bad that I had no idea when it happened. The boat ran fine to my knowledge when I winterized it last year. The tech said it could have happened by sucking up a rock and "tweeking" the shaft. I do not doubt this theory at all. What I find suspect is for 5 years I ran an aluminum sleeve and stainless steel impeller and never had any issue. This time last year I made the switch to a poly lined sleeve(?) and a aluminum impeller. Sucking up rocks on the river is nothing new it happens several times every year. This is the only thing I can come up with. I have heard you shouldn't run a SS sleeve and a SS impeller together, but have no experiance with this set up.
1. Do you guys think this was something freak that can happen with any set up?
2. Do you think the combo of poly sleeve and aluminum impeller is inadequate?
3. Is aluminum sleeve and SS impeller the preferred set up.
All that being said I usually run the boat by myself, not a lot of weight, and have didn't notice any performance differences when I made the changes.