Shortening Evinrude Drive Shaft

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mmorasci
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Location: Coeur d Alene ID

Shortening Evinrude Drive Shaft

Post by mmorasci » Mon Jun 18, 2012 9:23 am

My current project is an Ultra Pierre with some modifications. One of the modifications is in the outboard power. I am using a '55 (I think, maybe a '57) Evinrude 18HP twin for propulsion but to get it to fit in the location designed for it, I had to cut down the tower significantly. I have been able to fit the water tube and shift mechanism and am ready to work on the drive shaft. Question is, how best to shorten the drive shaft? Would I do fine by cutting the center section out welding and /or welding and then sleeving (or how about the need to balance afterwards?) or do you think I would have better success by trying to recut splines on one end or the other after shortening to the proper length? I have full machine shop capability to work with. This part of the project has been sitting for a couple of years while I have been working on the rest of the boat and I don't remember if the drive shaft is hardened or not nor have I tackeled this type project before so I'm looking for advise on the pitfalls to avoid. The total length of the shaft will be approximately 12" when finished.

Any advise is greatly appreciated.

Thanks,

Mike Morasci

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ttownshaw
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Re: Shortening Evinrude Drive Shaft

Post by ttownshaw » Mon Jun 18, 2012 9:49 am

I would think shortening and remachining the tines would be the better option.
Bill

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mmorasci
Posts: 46
Joined: Wed Mar 03, 2010 3:45 pm
Location: Coeur d Alene ID

Re: Shortening Evinrude Drive Shaft

Post by mmorasci » Tue Jun 19, 2012 6:50 am

Thanks, that's what I was thinking too.

I checked the shaft with a file last night, and it marked with little effort so I guess it isn't hardened. The reason for the post is I've had two different people over the years, tell me they have tried to do this operation before each had no luck. Frankly, I don't remember who they were or why exactly they had problems so I thought I'd throw this question out and see if anyone had anything to share. When I get the engine tower back from welding I'll fit things together measure the needed length and begin cutting.

I truely appreciate the feedback.

Mike Morasci

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vettepilot
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Re: Shortening Evinrude Drive Shaft

Post by vettepilot » Wed Jun 20, 2012 2:07 am

Years ago Dad & I shortened a 15hp Long Shaft Mariner by taking out the ext block then cutting and rewelding the drive shaft (we didnt have access to fancy equip lol) anyway cut the middle out of the shaft then cut the ends to about 15deg each and welded them together...That engine is still going 20yrs later... :wink: If we had access to be able to redo splines etc would have been easier :wink:
The Bitterness of Poor Quality, Remains Long After The Sweetness of Cut Price is Forgotten...Thanks Dad R.I.P.

mmorasci
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Re: Shortening Evinrude Drive Shaft

Post by mmorasci » Thu Jun 21, 2012 11:26 am

Vettepilot,

I appreciate the input. Nice to hear from someone who tackled a similar project, glad to hear the mod's you and your Dad made are still working. That takes a lot of the fear I had off in doing a similr modification.

Let's see.... One Vote Machining, One Vote Welding...Hmmmmm.

I checked with my local supplier and they can fabricate a form cutter quickly and for little expense. Since my machining skills are far better then my welding skills I think I'll try that route.

Thanks guy's.

Mike Morasci

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