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Old 10-29-2014, 12:40 AM   #21
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Maybe a prop shop?
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Old 10-29-2014, 02:23 AM   #22
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Quote:
Originally Posted by Edelweiss View Post
Is the mechanic competent with inboard engines, gear and shafts or is he just guessing?? It could also be just out of alignment?? Which can be corrected by readjusting the engine alignment to the shaft. You need someone who is familiar with aligning shafts to check it out in the water, prior to hauling the boat out. If it is a shaft problem, then the shaft needs to be sent to a shop for repair or replacement. It could also be a dinged propeller. That will also cause a vibration.
Most excellent advice!!!
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Old 10-30-2014, 04:21 PM   #23
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Clearence requirements vary greatly between metal bearings with usually oil lube , and cutlass bearings that are water lubricated.

Dont mix apples and oranges.
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Old 11-03-2014, 06:52 PM   #24
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When a new propeller shaft is made how close to the size in question should it be? There must be a tolerance of how much less than the specified size it can be. I'm sure the stern (cutlass) bearing only comes in one size and the shaft is supposed to be fit to the stern bearing. One wouldn't want it tight of course as it would probably heat up and self destruct. One wouldn't want it loose enough to "rattle" around in the bearing causing excessive wear and noise.

Should a "clunking sound" be heard if one tried to move the shaft back and forth? I do hear a clunking sound and I think it's not right but how do I know how loose or tight the stern bearing to shaft fit should be? My shaft is 1.25" dia. How many thousands of an inch tolerance should be maximum? As the prop shaft becomes smaller how small is too small? I had a new prop shaft made and I think it's smaller than my 10 year oil shaft. I want to call the yard boys on this or be assured "that's normal". And I don't want to cause the yard any unnecessary trouble and expense. But I definitely want the stern bearing to fit the shaft properly.
Eric, I just went through this with my cutlass bearings. Your size shaft should have clearance of between .003" and .008", which is something you should be able to measure yourself. If it is greater than that, the cutlass bearing needs to be replaced, or the shaft is out of spec.
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Old 11-03-2014, 06:56 PM   #25
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Originally Posted by manyboats View Post
Ski,
It feels and sounds like the bearing is in perfect alignment w the shaft as the contact seems sudden when I jerk the shaft back and forth. I'd rather have .005" slop but I'm quite sure this is going to last for years. The last setup went 8 years w practically no wear .. should be fine. And yes I've seen boats w lots of clearance and the skipper is say'in "what slop?".

And of course another opinion in that direction is a plus.
Here's what the Navy has to say on the subject:

Cutless Bearing Clearance
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Old 11-03-2014, 06:58 PM   #26
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Learn quickly...some mechs/marine techs can bleed you dry for what they think
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Old 11-03-2014, 08:38 PM   #27
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Exactly. Caveat Emptor. Verify a bent shaft with a dial indicator on the shaft behind the trans.As to the original post concerning a loose cutless, My opinion is that if it clunks it aint right. But you may be fine with it. Probably never even notice it. Myself, I could not splash it until it was to my satisfaction.
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Old 11-04-2014, 07:15 AM   #28
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And remember the shaft saver repair parts , an inside out setup that works well.

www.shaftsaver.com/shaftsaver.htm
Welcome to the ShaftSaver™ web site. This web site tries to clearly demonstrate how our claim that you may never buy another prop shaft can be true, but ...
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