Question about a bent prop shaft

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JMichael

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I'm looking at trying to breath some life back in to an 89 Mercury 8hp. The only problem that I've discovered so far that I'm not sure what to do with, is the prop shaft. If I attach a pointer to the cavitation plate and rest it even with the top edge of the prop shaft, then slowly rotate the shaft, I can see that there is an 1/8th inch (1/16th high and 1/16th low) of warp in the tip of the shaft. Buying a new shaft is out of the question because that and the other parts required to fix this motor would put it well above what it's worth. So what I'm wondering is whether a machinist could straighten that shaft or not. Anyone had any experience with doing this before?
 
If he knows his stuff, yes a good machinist can get it straighter. I bent a shaft on a 6 hp rude once, took the shaft out and took it to the shop where I used to work. A bud of mine put it in the lathe and found that it was 112 ths. out of round. He then took an oxyacetylene torch with a small tip which produced a VERY small & thin flame. He then heated certain sections which caused the shaft to bend the in the direction needed . In all it took about an hour or so of doing that to get the shaft to less than 3 ths out of round. I reassembled it all and never had any leaks from the seals. The boat ran true and I ran it like that for 3 more years till I sold it.
 
Chuck it up at the bend & hit the high side with a rubber hammer till it's straight.I have straighten many a shafts in a lathe with no heat.
Alot more involved but basically what I do.
 
I wish I had access to a lathe that I could chuck it up in but unfortunately all I own is a woodworking lathe. I have seen smaller shafts of a different type straightened before in a lathe but wanted to get some verification on doing the same process with a larger shaft like this prop shaft. Thanks for the input guys.
 
Got my service manual in the mail this afternoon and according to it, the shaft gets replaced if there is .006 or more of wobble. So I'm hopeful the machinist can straighten it out to .005 or lower.

Now if I can just locate a drive shaft bearing removal tool for this motor. :roll:
 

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