Shaft coupling is a rusty lump, how to remove

[JimF]

My shaft coupler has no discernible bolt heads, and appears to be pretty well rusted onto the part it bolts onto(I don't know what to call that). I may have to cut it off the shaft and this no name part. It appears that the no-name part can't be removed without first removing the coupler, so that is out unles someone can tell me a way to do it. Transmission is direct drive (I think).

The boat goes on the hard this week so it is time to start, plan is to first cut off what left of the bolt heads and then try to drill the bolts out with left handed drill bits. followed by easy out bits to remove whats left out. I need to do this because the coupler is disintegrating and my Ranger 29 has so little room between the coupler and the stuffing box that I can't change the shaft packing without removing the coupler. Changing the packing is long overdue.

I am looking for advice I guess on how easy it is or isn't to replace this no-name piece that the shaft coupler bolts onto (3 bolts), if it turns out I need to do that, and also advice on drilling out bolts this rusty.



Thanks

[Dave Neptune]

JimF, if you have fair access and can run the engine against the dock lines try a wire brush. With the engine running in gear you can hold the wire brush against the rusty stuff and things will appear as the rust is removed, try forward and reverse. You can also just use more "Norwegian steam" and just wire brush by hand if you have the energy. Whatever feels comfortable to you.

Spray some penetrating oil into the rust as you are brushing/or holding the brush. You will be surprised how much will come off~then you can see what you are up against.

Do you have the MMI manual?

Dave Neptune

[Administrator]

Eye protection!

Bill

[romantic comedy]

I would get all dressed up with gloves, eye protection, hat and body protection. Then watch for fuel sources and go like hell with my Makita grinder. I love making sparks!!

Get back, everybody out of the way!!

[Al Schober]

Jim,
The 'no name' part is the output flange of the transmission. The part behind it is the shaft coupling, which has 3 bolts (direct drive) connecting it to the transmission.
To clean up the corrosion, I'd use an angle grinder with a wire wheel - one of the coarse ones where the wires are twisted into ropes. Gloves, long sleeve shirt, and safety glasses with side shields (or full face shield). You do NOT want that stuff in your eye - your PCP will send you right to an ophthalmic surgeon.
Depending on what's left after cleanup, you may be able to get the bolts started with a pair of vise grips. My next choice would be to cut a slot into what's left with a Dremel tool, and then use an impact screwdriver. Final option is left hand drills. I would advise against easy-outs - break off one of those suckers and you're in deep trouble.
But after you get the bolts out - then what? The coupling is probably corroded to the shaft, and it doesn't sound like you have much room to work. You can fight with it or just hit it with the checkbook - cut the shaft aft of the coupling, then replace the shaft and coupling. Don sells a split coupling that sounds perfect for your application.

[sastanley]

Jim...we need some pics. They really help a lot. If you decide to grind on it first, Al's advice is good.

I fought a coupler/shaft issue several years ago...all these peeps helped me out quite a bit without resorting to drastic measures..simple, but methodical steps tackled it.

[ndutton]

If you're considering brushing a spinning coupler I'd forget the long sleeves and any gloves should be the tight fitting surgical type.

[tenders]

The coupler in that condition is never going to be salvageable. I would cut the shaft coupler off the shaft by running a Sawzall parallel to, and close to, the shaft. Do that twice, taking care not to nick the engine side coupler, and the rusty part will fall off the shaft with a bit of inertial persuasion (i.e., a hammer). Then cut off any lingering bolts.

Save the wire wheeling for the shaft once you get the coupling off. Then replace the coupling with the Moyer split coupling - that is exactly what you want if you need to mess with the coupling to get at the packing. (Also consider replacing the flax packing with Teflon packing.) Smear antiseize everywhere there is metal-to-metal contact, and the coupling will probably never need to be replaced.

[JimF]

Picture added to original post

I uploaded a picture that can be viewed on the original post.

Thanks for the replies so far, I will start this job on Saturday, boat is in Maine and I am in Conn.

[hanleyclifford]

Wow

That is about as bad as I've ever seen. Looking at the cracks and separation one wonders if a cold chisel and ball peen might get it off. I can see some possibilities for gaining some working room by shortening the shaft log hose and the packing assembly itself, but first the thing must be disassembled. The caution now is to try to save the gear box out put coupling but even that is problematical since likely there are some nasty threads rusted into it. Start off with a little tap tap and see if that coupling might fall apart enough to free the shaft.

[Dave Neptune]

Wow again

What Hanley said. You should really look into shortening the log as that is where the drip is and it looks like your coupling caught most of the drips.

Dave Neptune

[JimF]

Removing the output coupling

Can someone describe what holds the output coupling on? This part has me fearful of cutting the shaft coupler off, I just ordered a new direct drive output coupler ( I have the split coupler for the shaft already), but I am afraid of damaging something between the two couplers in cutting the shaft coupler off.

I just am wondering what is between the two pieces, is there some sort of nut on the shaft side of the output coupler?

[hanleyclifford]

Can someone describe what holds the output coupling on? This part has me fearful of cutting the shaft coupler off, I just ordered a new direct drive output coupler ( I have the split coupler for the shaft already), but I am afraid of damaging something between the two couplers in cutting the shaft coupler off.

I just am wondering what is between the two pieces, is there some sort of nut on the shaft side of the output coupler?

If you have conceded the loss of the output coupling the plan is simplified. If you try to make a cut at the junction of the couplers with a sawzall or other such tool there is the risk of hitting the nut and shaft. From the look of that picture a better plan would be to first attack with cold chisel where the coupler is rusted and cracked with the view of destroying it and freeing the shaft. Then cut the heads off the three cap screws (forget ever getting a wrench on them). Next try to drive the chisel between the coupler halves with a view to separating them and exposing the remains of the screws.

[tenders]

I think there is too much metal there to break anything off with a cold chisel, except your sanity. I would not try to cut or chisel perpendicular to the shaft, or at the junction of the two couplers, for fear of cracking or distorting the face of the engine coupler or gouging the shaft. At least, not yet!

There is a nut in the center of the ENGINE coupler holding it to the engine. The nut is slightly inset from the face of the coupler, as I recall. But I'm guessing your engine coupler will clean up just fine after you get the shaft uncoupled; you should not have to perturb this nut nor replace that coupling for this job.

On the SHAFT coupler, there is a keyway with a square metal key locking it to the shaft, and there are likely one or more setscrews holding this key in the shaft/coupler keyway.

The bolts holding the couplings together are threaded into the engine coupler. One can imagine those bolts breaking off and needing to be drilled out - that won't be much fun. Getting those out is another reason to use the Sawzall - you might be able to unscrew them using the attached fragments of the coupler after you've cut the shaft out of it.

On my boat, I doubted the strength of the threads in the engine coupler, so I replaced the stock bolts with longer bolts that have nylock nuts in addition to being threaded into the engine coupler.

Finally, there may come a time at which the hours you spend trying to finesse this are simply not worth the finessement. Worst case: just cut the shaft; a replacement shouldn't cost more than $300. Get it out of there and you'll have more room to chop out the shaft coupler without damaging the engine coupler.

[JimF]

Rusty coupler successfully removed - next problem

Thanks for all the advice, the hard part was getting the sleeve of the coupler off the shaft, once I did that, by cutting all the way around at the juncture of the sleeve and the bigger part of the coupler, I made two parallel cuts (very difficult), can't get the right tools at it because there isn't enough room. Best success was with a dremel with a 3 inch cutoff wheel. Cast iron is hard!

Pictures attached. my problem now is what is the trick to getting the output coupler off the tail shaft, I can get an open end wrench on it but the motor just spins when I turn it even in both forward and reverse gear. I had to leave at the point where I got to that (boat is in Maine and me in CT) so I didn't have much time to play with it. It looks like there is some kind of retainer on it, but even so I think I am going to have to lock the motor somehow in order to spin this nut off. Is there a retainer and how do you get that off, and how do you lock the motor, or is that nut on the output coupler reversed threaded?