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Shaft Coupling rusty: repair or replace?

Posted: Oct 13th, '20, 09:14
by SteveM
My shaft couplings are rusty.
I was thinking about trying to remove the rust (in place), hit them with Ospho, Paint, then CorrosionX.

Seems like a bit of work in such a tight space to work. I envision black and blue ribs.

It might be easier just to replace them with new couplings that I can paint and protect on the bench prior to putting in the boat.

Any tips on this?

Is removing them getting into a can of worms? If I removed them would I need to re-align shafts, etc?

Re: Shaft Coupling rusty: repair or replace?

Posted: Oct 13th, '20, 10:01
by Stephan
Steve-
I've paid some tuition on your project. I needed to straighten a shaft and the coupler had to come off. I thought my couplers were in good shape with minimal rust. However, pressing it off was not easy and arguably much more work than fussing with just painting them in place.
To put is succinctly do not use stainless hardware when pulling the couplers (http://bertram31.com/newbb/viewtopic.ph ... t=+coupler Matt - thanks again for making this all work)
I was lucky as the coupler largely aligned itself on the shaft - or at least acceptably so for my work.
I trusted that since the engine and the strut were in the same place when I removed the shaft I did not need to realign.
Good luck.
Stephan

Re: Shaft Coupling rusty: repair or replace?

Posted: Oct 14th, '20, 07:49
by John F.
Paint in place. Removing may involve cutting the shaft and new shafts and couplings. Or not, but why get into it

Re: Shaft Coupling rusty: repair or replace?

Posted: Oct 14th, '20, 09:03
by Carl
No need to align motors after pulling, but it is a great time to check it.


If couplings were "fit" together and assembled with anti-seize, then sprayed up every so often with paint or lube they should come off in a relatively short time. For me, it is usually a 10-minute job.

If they are the old solid style couplings that were pressed on years ago or even the split couplings...they can be a bear to remove and it's gets worse each year.

Repair or replace...you have to pull them to see if bad needing to be reworked or replaced.

Is it a can or worms...yup.

If you cruise local and never any need to get back in water ASAP you can leave the job till you need to pull shafts, change packing gland or go over to the dripless packing.

Now if you cruise to distant ports...mangle a shaft or strut and limp into another marina where you cannot work on your own boat, or do not have the tools this can be a pricey job from a yard. Coupling may pull off easy or it becomes a job of drilling out twisted off set screws, cutting the coupling off or what the mechanic in my old yard did if the coupling did not come off relatively easy...sawzall to the shaft. Now you need a shaft or two.

Or if your a person that needs to have boat running when fishing is hot...do you want to be screwing around trying to get coupling off then, OR in my case....work like this always seems to happen during a heat wave.

Only you can make the call here.

Do it when you have time OR do it when you HAVE to.

Re: Shaft Coupling rusty: repair or replace?

Posted: Oct 14th, '20, 11:21
by SteveM
Yeah...I think I'm gonna crawl in there and clean them as best as possible till I have the boat in the yard in 2021. Thanks for all the feedback.

Re: Shaft Coupling rusty: repair or replace?

Posted: Oct 14th, '20, 14:29
by Marshall Mahoney
After sanding/solvent wiping, paint with a "surface tolerant epoxy." I used Ameron Amerlock 400, but lots of other options available. Also, after sanding-- especially if you use power tools, wash down the cockpit thoroughly. A side grinder with a bronze cup wheel will make a rust-dust cloud that will leave micro rust stains the next morning that are a bitch to remove (learned the hard way).