Don't think so. The vibration would indicate alignment. It's not as easy as you might think with the coupling tube that is used as opposed to the plate couplers normally used (or whatever their called). Any play in the shaft at the coupler end makes it more difficult.
If there is any play at all (1/16" is max before replacement) in the cutlass bearing any slight misalignment will be magnified and cause the shaft to flop around as RPM's and load increases. This could be the problem if you did not replace the cutlass bearing when you replaced the shaft. The old shaft being bent will have provided considerable uneven wear to the bearing over time. I would run the motor disconnected from the shaft and insure it is not the problem (doubtful), then attach shaft without prop and run it. If no vibration problems then problem would likely lie with prop itself. Also make sure your stuffing box has been properly packed and did not wear the packing unevenly due to the prior bent shaft.
As far as cavitation how are you detecting that - loss of thrust at RPM? If so, I'd be looking at the prop and it is experimentation at that point. If its a resonant noise or vibration it may not be cavitation but something else and I would focus on alignment while in the water and hope it corrects the problem. 1250 RPM seems awful low for cavitation to be an issue. Aeration and/or ventilation are more likely but I wouldn't think so looking at your configuration or any sailboat hull with inboard drive for that matter. I'm not familiar with the max props or feathering/folding props in general. Good Luck
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Sent from my Android phone with K-9 Mail. Please excuse my brevity.
Wayne -
When I first put the motor in, the shaft had enough discoloration that
it was easy to figure out where it was before, so that didn't change.
When I got the new shaft (old one was bent), I'd already drilled for the
mounts, so, if there was a difference, it should only have been slight.
I know there is enough distance between the prop and the hull - I've
measured that since it was an early suggestion made to me.
The shaft diameter is 2", and I know there's not a point where there's
80" of unsupported shaft. There is quite a distance between the engine
and the coupler. I'm at home, not at the boat, so I can't tell you
exactly. But it seems there's about 16 - 18" there. Could that be part
of the problem?
Anne Racel
4 Degrees
http://boatjournal.stuffandjunk.net
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