Stern tube hose replacement Yamaha 30

Dec 20, 2020
9
Yamaha 30 tall rig Galiano Island
I plan to replace the, likely original, hose when hauled out this spring.
Samurai is the forward (under vberth) model with a yanmar ysm12.
I would be most appreciative to acquire some tips from someone with experience.
I’ve read the manual but it doesn’t show where the shaft separates. I wonder if its at the connection to the transmission or does that thrust connection join two pieces of shaft.
Any of you fellow Y30 owners ever tackle this?
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
Wow...I had to look that up...sure enough...engine under the V!

12AEF733-8F0A-405E-AEEB-FACB4FB8FE7C.png

From photos I could find, I think you are right. You will need to disconnect the shaft and coupling from the transmission output flange, then separate the coupling off the shaft. Then you would be able to slide the stuffing box and hose off the shaft, and replace.

I am not familiar with the “thrust connection”, so maybe that is another alternative.

I replaced my 30-year old shaft a few years ago on my O’Day 322. I was trying to not destroy the shaft until I knew if I could get a new one back in without dropping the rudder. The hardest part was getting the coupling off the shaft...

This video may give you some insight into how I did it...

And this is putting it all back together...

While I replaced the propeller shaft and you are not, the steps are not much different.


Good luck,

Greg
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
One other note...

Apparently the Y30 has a 20 foot long prop shaft (hope you don’t need to replace that)... and has pillow blocks to support the shaft along the way...maybe those are the thrust connections you are referring to.

Either way, I am not sure then how you get the shaft log hose off... I assumed (incorrectly) that the shaft log was close to the engine....but apparently the shaft runs the length of the boat (hence the pillow blocks)...

I saw this photo on line but it doesn’t show where the shaft exits the boat...

6B0B0EB0-DF07-4C63-8622-764069A6DDE7.jpeg

I guess I am not much help....sorry.


Greg
 
Aug 27, 2009
43
Yamaha 33 Portland
I've done this a few times. It's one long shaft from the reverse gear to the propeller. Disconnect the coupler in the engine space, loosen the set screws in the pillow block, (there might be an additional locking hardware at these blocks). Remove the propeller and the zincs. Pull the shaft - it will just clear the rudder off to the side.

Replace the pillow block. It can't be changed out in the water so this is your chance to do it - don't skip it. Might as well replace the cutlass bearing. Might as well true or replace the shaft.

The Y33 has a "hidden" bearing just inside the hose you want to replace. The yard discovered it. This job with a new shaft and bottom paint cost me 5k last spring. The boat is running super smooth now.

Richard
SV Seven

Capture.JPG
 
Last edited:
Dec 20, 2020
9
Yamaha 30 tall rig Galiano Island
I've done this a few times. It's one long shaft from the reverse gear to the propeller. Disconnect the coupler in the engine space, loosen the set screws in the pillow block, (there might be an additional locking hardware at these blocks). Remove the propeller and the zincs. Pull the shaft - it will just clear the rudder off to the side.

Replace the pillow block. It can't be changed out in the water so this is your chance to do it - don't skip it. Might as well replace the cutlass bearing. Might as well true or replace the shaft.

The Y33 has a "hidden" bearing just inside the hose you want to replace. The yard discovered it. This job with a new shaft and bottom paint cost me 5k last spring. The boat is running super smooth now.

Richard
SV Seven

View attachment 191416
I've done this a few times. It's one long shaft from the reverse gear to the propeller. Disconnect the coupler in the engine space, loosen the set screws in the pillow block, (there might be an additional locking hardware at these blocks). Remove the propeller and the zincs. Pull the shaft - it will just clear the rudder off to the side.

Replace the pillow block. It can't be changed out in the water so this is your chance to do it - don't skip it. Might as well replace the cutlass bearing. Might as well true or replace the shaft.

The Y33 has a "hidden" bearing just inside the hose you want to replace. The yard discovered it. This job with a new shaft and bottom paint cost me 5k last spring. The boat is running super smooth now.

Richard
SV Seven

View attachment 191416
thanks very much, Richard! Great level of detail and helpful information.
 
Dec 27, 2020
29
Yamaha 30 - Tall Rig Vancouver
thanks very much, Richard! Great level of detail and helpful information.
I'm also looking to do this same job on a Y30. Any information on parts for the tube (are there generic parts for that) and thrust bearing. I have the cutlass bearing.

Cheers!

Peter
 
Dec 20, 2020
9
Yamaha 30 tall rig Galiano Island
I'm also looking to do this same job on a Y30. Any information on parts for the tube (are there generic parts for that) and thrust bearing. I have the cutlass bearing.

Cheers!

Peter
Hey Peter. Did you ever get around to doing this? It’s on my 2022 haulout plan and I am just now beginning to research parts sourcing. Any leads you have would be much appreciated.
 
Dec 27, 2020
29
Yamaha 30 - Tall Rig Vancouver
Hi Samari,

Yes I did. I’ve done a LOT of work on my Yamaha 30 since I bought it as a project boat last year - lol. At the time it wasn’t running and I knew it needed some major work. I decided to rebuilt the YSM12 while in the vbirth and dug deep into the boat replacing and repairing many things. It’s been an adventure and it’s been satisfying.

My stern tube hose was original. And I know that because I bought the boat from the original owner who had had it since new for 40 years. And he said he never replaced it. The tube had a lot of cracking. It made me nervous just looking at it. The good news is you can replace the rubber tube hose with a similar diameter and length of high pressure hose. That’s what it was originally by the looks of it. You can buy it from Greenline in Vancouver and for that length it’s about $25. Buy their better clamps and double clamp each end.

I’m sure you can see you’ll need to pull the boat and remove the shaft to do it. Once on the dry, to do that you need to undo the coupler from the engine and release the shaft from the coupler by undoing the bolt at the end of the shaft. Read the manual carefully. It is a reverse thread at the end of the shaft in most cases meaning you would turn it the opposite way than typical. Confirm for yourself in the manual that is true. Its a bronze shaft and I’ve heard if you go the wrong way with force you can break the end of the shaft off so really think it through. That is a very very expensive problem but happily it’s easily avoided. You also have to remove the several easily dissembled items from the thrust bearing - very easy to do as the manual shows. The shaft does clear the rudder so no worries. The shaft is about 11 feet long so bring a friend. My stuffing box was working but I decided to pull that apart too and do some custom work on it.

I replaced the cutlass bearing and put two additional set screws to hold it but that was me enjoying doing a good job of it. You can now get the exact needed cutlass bearing online. It’s 22mm in a standard diameter hole in the case of my cutlass.

I can go into more detail and I have pics. Send me a PM and I’m happy to tell you more about it. I hope that’s a helpful start.

Cheers,

Peter
 
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Dec 27, 2020
29
Yamaha 30 - Tall Rig Vancouver
One follow-up. I didn’t need to remove the prop. I have a folding prop so perhaps that’s helpful but a two blade prop I expect would also clear.