Help me identify this please

[djousset]

Engine is Yanmar 2gm20f with Kanzaki KM2P transmission. Is this rusted part the output coupler?

There are two set (?) screws opposite each other, one has a nut and a hole in it for a safety wire and the one you see here does not. I assume this piece separates from the red piece when the bolts are loosened?

[newhaul]

Originally Posted by djousset

Engine is Yanmar 2gm20f with Kanzaki KM2P transmission. Is this rusted part the output coupler?

There are two set (?) screws opposite each other, one has a nut and a hole in it for a safety wire and the one you see here does not. I assume this piece separates from the red piece when the bolts are loosened?

Yes once you unbolt them they will separate the red one is the engine side of the shaft coupling and the rusty one is the shaft side

[djousset]

Thanks, should this be replaced due to the rust? And if so is another straight coupler best or can/should I consider a tapered or split coupler? Not sure if that's possible, or if there are advantages. If I do this myself I assume I would need to re-align the shaft.

[wingssail]

Originally Posted by djousset

Engine is Yanmar 2gm20f with Kanzaki KM2P transmission. Is this rusted part the output coupler?

There are two set (?) screws opposite each other, one has a nut and a hole in it for a safety wire and the one you see here does not. I assume this piece separates from the red piece when the bolts are loosened?

Yes, this is the shaft coupling. The red part and the rusty part are called flanges. They are joined with the four bolts and when joined connect the transmission out-put with the propellor shaft.

The set screw bolts with the holes for wires keep the propeller shaft secured in the flange. Once removed the propellor shaft can slip out of the flange. Inside the flange there is a small piece of metal called a key which fits in matching grooves in the end of the shaft and the inside of the flange. This key keeps the shaft turning when the flange turns.

So the shaft connects to key and the key connects to the flange and the flange connects to the transmission and that's the house that jack built.

By the way, sizing wire is meant to be put through the holes and wrapped in such a way that those set screws cannot turn and come out which would release the shaft. You'll know if that happens.

[wingssail]

Originally Posted by djousset

Thanks, should this be replaced due to the rust? And if so is another straight coupler best or can/should I consider a tapered or split coupler? Not sure if that's possible, or if there are advantages. If I do this myself I assume I would need to re-align the shaft.

You can take out that rusty flange and clean it thoroughly then paint it with rustoleum or something. Then put it back in. Taking it out may be tough since it is rusted. Use anti-seize compound on reassembly. You will not have to re-align the shaft. Be sure not to lose the key and use seizing wire in the set screws.

One thing to look out for is the shaft packing. Just behind the coupling the shaft goes out of the boat through a shaft log, or a big tube. It may have flax or other kind of packing to keep sea water from coming in while allowing it to turn. If you monkey around with the shaft too much you may disturb the packing and it may start to leak. Shaft packing can be re-tightened and that's another lesson. Not for today. Read up on it.

BTW, I am sure some expert will come in and correct my terminology. It's OK

[djousset]

Originally Posted by wingssail

You can take out that rusty flange and clean it thoroughly then paint it with rustoleum or something. Then put it back in. Taking it out may be tough since it is rusted. Use anti-seize compound on reassembly. You will not have to re-align the shaft. Be sure not to lose the key and use seizing wire in the set screws.

One thing to look out for is the shaft packing. Just behind the coupling the shaft goes out of the boat through a shaft log, or a big tube. It may have flax or other kind of packing to keep sea water from coming in while allowing it to turn. If you monkey around with the shaft too much you may disturb the packing and it may start to leak. Shaft packing can be re-tightened and that's another lesson. Not for today. Read up on it.

BTW, I am sure some expert will come in and correct my terminology. It's OK

This is all super helpful, thank you. (I'm trying not to ask the really stupid questions so thanks for intuiting my confusion).

I was thinking I should remove that flange and clean or replace it. Good tip on the key......I had an incident with the wheel key that I prefer not to revisit.

I've dealt with the packing gland before so have that on my list as a
must-check-out.

No mind on the "experts", I appreciate the (newbie) user-friendly straight talk.

[Calif.Ted]

Is it possible the red part is a drivesaver flexible coupling that requires the bonding wire shown ? I take off loose rust and scale with brass brush on drill and paint with Rustoleum rusty metal primer and gloss black. Wouldn't remove, just clean a little and paint, and maybe safety wire the set screw with the hole.
https://www.globecomposite.com/DriveSaver

[boatpoker]

Originally Posted by djousset

No mind on the "experts", I appreciate the (newbie) user-friendly straight talk.

I worked on removing mine from the shaft for three very long days in 100F in florida ...
Then I went to Harbour Freight and bought a disc grinder and cut it off.
Hope yours goes better than mine.

[s/v Jedi]

Hi Diane, what works really well for cleaning and painting those rusty flanges is a product called POR-15 which comes in handy kits. POR stands for Paint Over Rust. Use gloves because it’ll stick to your hands for weeks.

Here’s a link: https://por15.com/collections/all/pr.../stop-rust-kit

[Uncle Bob]

If there is no problem associated with it then I would set to work with a wire brush, thoroughly clean any loose rust and paint with rustoleum paint or similar. The red part looks to me to be a drivesaver of some brand. If the coupling is disturbed then an alignment needs to be done.

+ Just noticed Jedi's post, POR is a great product.

[newhaul]

Originally Posted by djousset

This is all super helpful, thank you. (I'm trying not to ask the really stupid questions so thanks for intuiting my confusion).

I was thinking I should remove that flange and clean or replace it. Good tip on the key......I had an incident with the wheel key that I prefer not to revisit.

I've dealt with the packing gland before so have that on my list as a
must-check-out.

No mind on the "experts", I appreciate the (newbie) user-friendly straight talk.

Is there an issue with it ? If not then why even worry about it .
In my boat the coupler needed to be removed and replaced old was 3 bolt new is 4 bolt. It took 3 days and a can of deep creep with proper pullers to remove it .

If there is no issue with yours just cosmetic then clean the lose rust off and repaint with rustolium paint . Mask off any parts you don't want painted and spray away .

[Sailmonkey]

That shaft couple, while lightly rusted, is in no way needing replacement. I’d just give a coat of corrosion x and move on.

To remove a coupler of an age that allows it to look like that will take a puller and some serious work, or cut it off. If it’s removed it’ll likely not go back on the shaft correctly. If it’s cut off, a new one should ideally be fit to the shaft at a machine shop. That means the shaft comes out of the boat.

[wingssail]

Originally Posted by Sailmonkey

That shaft couple, while lightly rusted, is in no way needing replacement. I’d just give a coat of corrosion x and move on.

To remove a coupler of an age that allows it to look like that will take a puller and some serious work, or cut it off. If it’s removed it’ll likely not go back on the shaft correctly. If it’s cut off, a new one should ideally be fit to the shaft at a machine shop. That means the shaft comes out of the boat.

Getting the flange separated from the transmission should be easy (not guaranteed but should be). On mine I tapped a screw driver blade into the gap and rotated it and did that some more. Eventually it came free.

Getting the flange off of the shaft may be harder. Once the flange is loose and free to move forward and aft, I put a socket into the gap then retightened the bolts, sort of like a wheel puller in reverse, heat and PB Blaster may help. In the end I hit it with a big hammer.

You have to decide if you really want it off. A clean-up and repaint in place may be enough. I took mine off because I didn't like the idea of something that was stuck when it shouldn't be.

BTW, what is that green wire? I am not familiar with that, wouldn't it get wrapped around things if the shaft was turned?

[Uncle Bob]

Originally Posted by wingssail

Getting the flange separated from the transmission should be easy (not guaranteed but should be). On mine I tapped a screw driver blade into the gap and rotated it and did that some more. Eventually it came free.

Getting the flange off of the shaft may be harder. Once the flange is loose and free to move forward and aft, I put a socket into the gap then retightened the bolts, sort of like a wheel puller in reverse, heat and PB Blaster may help. In the end I hit it with a big hammer.

You have to decide if you really want it off. A clean-up and repaint in place may be enough. I took mine off because I didn't like the idea of something that was stuck when it shouldn't be.

BTW, what is that green wire? I am not familiar with that, wouldn't it get wrapped around things if the shaft was turned?

That green wire is an earthing path across the nonconductive drivesaver. Connects the engine and all else neg to the prop shaft/prop. Not sure that it is at all necessary provided that the shaft is fitted with sacrificial anodes.

[wingssail]

Originally Posted by Uncle Bob

If there is no problem associated with it then I would set to work with a wire brush, thoroughly clean any loose rust and paint with rustoleum paint or similar. The red part looks to me to be a drivesaver of some brand. If the coupling is disturbed then an alignment needs to be done.

+ Just noticed Jedi's post, POR is a great product.

If the engine is not moved, and the shaft is straight, there should be no need for re-alignment.

You can easily check the alignment when you put it back together:

After the shaft is in the flange and secured then you slide the shaft and flange toward the transmission flange and just as they get close you check the gap all around with a feeler gauge. The gap between the flange face and the transmission face should be equal all the way around. If not then the engine needs to be moved by adjusting the engine mounts. Big job, try to avoid that. I've had my flanges off three times and the engine off the mounts once and I never had to adjust the alignment.