Should I cut this shaft?

[billabel]

I'm trying to pull the engine and need to disconnect the coupling. I've not seen any videos or photos of one this bad, plus it's very difficult to access. It's a Yanmar 2GM20F in a Victoria 30.

If it doesn't break loose from the engine, should I cut this shaft? I can pull the shaft out after the engine is out from the inside, and then try to get it off.

Any advice?

[Nekton73]

Assuming you otherwise want to save the shaft and consider it serviceable, I think I would try to pull the shaft out of the coupling first. You could start by drilling out what looks to be two set screws on either side (your pic attached with red arrows). That might free it up enough to pull it out.
If not, grind off the heads of the bolts holding the coupling together and attempt to chisel the two halves apart.

If still no joy, use an angle grinder to square the flange off the coupling, removing a lot of the rusted together material, and exposing a nice large flat mating joint to chisel again.
If still thwarted, cut the coupling along the axis of the shaft as close to the shaft as you can and use a chisel to split it apart that way. You could even cut it in halves or quarters.

[Searles]

No need to cut the shaft ,cut the heads off the coupling bolts and tap them out ,if space to g box is to small cut the bolts o under the nuts this will gain space ,once the engine is out ,remove the prop and key and pull the shaft inboard after slacking off the stuff box ,now much easier to work on ,if the coupling refuses to move carefully cut the shaft along the key way .

[wholybee]

It doesn't look to me like the coupler or shaft are salvageable. Best case I see, is that after a lot of work you cut the bolts, separate that shaft and remove the engine. Then you will be unable to get the coupling flange off the shaft, and thus be unable to install a new coupling, or have the shaft fit to a new coupling. You will need to cut the shaft to get the shaft out of the boat anyway.

So cut it.

[donradcliffe]

A new shaft will be about $500. Getting the coupling with penetrating oil, all thread, and
a series of sockets inside the coupling will probably take about 12 hours. Your choice.

[Bowdrie]

I would do as a previous poster said.
Cut the heads off of the bolts, drive them out.
Pull the engine, then pull the shaft.
Make sure there are no pins/setscrews locking the coupling to the shaft, if so then get them out by whatever means necessary.
Then if "homework" doesn't get the coupling off take it to a shop.
A 20-ton press will have no trouble.
Life will be easier if the new coupling is of "split" design using pinch bolts.
When you install the pinch bolts and coupling bolts don't be stingy with the anti-seize.

[skipperpete]

It doesn’t look terrific BUT, it seems like luck’s on your side…… that looks like a pinch coupling and possibly only a 2 bolt pinch so all you need to do is A. Confirm that it is actually a pinch/split coupling, B. Get a padsaw and cut the bolt shanks in the split, C. Drive a wedge into either or both sides of the split to open up the slot and it should come loose. This process relies on the bolts NOT being scalloped into the propshaft, if they are, you’re doomed to splitting the entire coupling which is actually not such a big deal with a pinch coupling, most of the hard work is already done ( the split) so only the flange needs to be sawn through, still not a walk in the park but way easier than sawing the length of the hub.

[NYSail]

My last boats coupling was that bad….. I k it the shaft side of the coupling then cleaned the transmission side. Had the shaft and prop serviced and they put on a new shaft side coupling.

Greg

[NYSail]

My last boats coupling was that bad….. I k it the shaft side of the coupling then cleaned the transmission side. Had the shaft and prop serviced and they put on a new shaft side coupling.

Greg

[pcmm]

Soak it in PB blaster (or your fav penetrating fluid) for a few days as a start. Then remove the coupling bolts and get the engine out of the way. As its a 2GM it shouldn't be hard to lift out of the way.

Once the engine is out you need a few tools to remove the coupling from the shaft. remove alll the bolts, setscrews etc on the shaft coupling.
1. MAPP gas torch
2. thick piece of steel (3/8") slightly bigger than the diameter of the coupling with 4 holes to match the bolt holes in the coupling
3. pieces of all thread to go into those holes and enough nuts to have 2 locked together on one end of each all-thread.
4. a socket with an outer diameter slightly under that of the shaft.

Assemble the steel plate with the allthread on the coupling. put the socket on the end of the shaft inside the coupling. Now tighen it up as much as you dare.

Take the torch and heat the coupling for a good long time (without burning down the boat!)

tigthen the bolts on the presser that you made above. Repeat. Heat, tighten, heat, tighten. Eventually the coupling will move.

Patience is key here

[NYSail]

Originally Posted by NYSail

My last boats coupling was that bad….. I k it the shaft side of the coupling then cleaned the transmission side. Had the shaft and prop serviced and they put on a new shaft side coupling.

Greg

Woops....... I cut the shaft side of the coupling. It was so corroded nothing else would work in my case.

[NorthCoastJoe]

Pull the engine, remove the prop and then pull the shaft out forward. Then you can put it in a vice to work on it not bent over in a tight hole. Or bring it to a shop with a press. The 2gm is easy to move around if you set a few 2x4s under it to slide it forward.

[more]

cut bolt head boath side with angel grinder.
and try pull rest bolt
later try hammer and rust remover couple time, later penetration oil and hammer again

[Tanqueray]

I think you should plan on replacing the shaft, coupling and strut bearing all at the same time (and consider a Volvo Penta rubber shaft seal).

I worked for a few days to press the shaft out of my coupling (and my coupling un-bolted fairly easily). You are in for a battle trying to get yours apart…and then you will probably find wear, cracks and other issues with the shaft.

After getting mine out, I replaced it.

https://youtu.be/4RlzgOOXhhQ?si=7nbVlp-segM65rZ6

https://youtu.be/FUjoyKfNZ_U?si=yAMQN_LfxCmhvOZG

https://youtu.be/0tHXzKb4liA?si=gWuy-CdWEaQHKjmM


Good luck,

Greg

[OS2Dude]

That coupler is in bad shape. As others have said, try grinding the bolt heads/nuts off and see if you can separate it. If your transmission is like the one on my Universal M25, the transmission flange is integral to the transmission and if it is bent or damaged you may be looking at a new transmission as well. Also be careful of using penetrating oils like PB Blaster as they can damage the seals in the transmission. Spray it into the cap and apply with small brush or cotton swaps.

For as rusty as the coupler is, I'd think about getting a new one. The connection between the coupler and the shaft is supposed to be an 'interference' fit and if the rust has gotten between the shaft and coupler, it won't be anymore. If you can get the shaft and coupler out of the boat, take it to a machine shop and see if they can use a press to push the shaft out. You may be able to keep the shaft, but shaft & coupler usually need to be machined together to achieve the desired 'interference' fit.

I had to cut mine two years ago because I could not get the shaft out of the coupler. I bought a new coupler and stainless shaft pre-machined.