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Y25 shaft seal

Sep 5, 2010
74
Yamaha 25 Hebe Heaven
It's been a sticky problem for me since the boat got to my hands.

1 of the screw threads have been damaged since previous owner. He used a trashed turn-buckle to push the bronze "plate" on that side, while using a usual screw on the other. This work-around has been used since then. But it's far from satisfaction, as the water keeps leaking in (very very slowly though!).

I tried re-thread it without taking it out, but only made the hole bigger. I am planning to fix this long-lasting pain in the coming regular maintenance on shore.

My preliminary plan is, take the whole thing out. Drill the hole through and re-thread it. So I suppose I need to remove shaft, but would it cause any shaft alignment problem?

I came across some modern shaft seal systems, such as Packless Seal System (PSS) and Lasdrop. Anyone tried these? Are they good and compatible to be fit-in a Y25?

Or any other ideas/suggestions are very welcome! Or any similar experience for share is also welcome!

Thanks!
 

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
I think you are talking about the stuffing box. In The Yamaha 25 , the female portion was fixed to the bilge by 4 bolts and nuts, and the male portion was movable and fixed by two struts.If you pack the Flax shaft packing properly , you can have no leaking for a long time without tighting the male portion by the nut in the strut. It sounds that one of the strut in your system was damaged . One solution is to get the strut welded back to the female portion , since you got the hole bigger , re-thread means you need a larger dia strut , that may not fit the original hole in the male portion , have a check.
It has to be done on the slip , re alignment of the shaft/ engine is required since you disassemble the system.
 
Sep 5, 2010
74
Yamaha 25 Hebe Heaven
Yes, I'm talking about the stuffing box. The struts on mine are not attached by welding. Instead, the female part has 2 threaded "holes" (not going through) for fixing 2 screws (left and right), and pressing the male part by a nut on that screw.

I am worried about re-alignment of the shaft after all the work done, as I have no experience on that.

Would it be difficult to do it? Any useful guidelines or online info can be reference?

Thanks!
 

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
This is useful information

http://www.yachtsurvey.com/alignment.htm


If you can weld the strut on the out of thread hole in the female part by yourself , you may not need to disassemble the coupler and steady from alignment problem .

Remove the 4 bolts that fixed the female portion. Slide the female portion along the shaft forward. Then the female portion is hanged in the shaft and you can get the strut welded to the female portion .
 
Sep 5, 2010
74
Yamaha 25 Hebe Heaven
Thanks again to Boffin for the useful information. I guess this will be useful when I replace the cutlass bearing some time later.

As for the stuffing box, I intended to remove the 4 bolts of the female part. Slide it up, drill the hole trough and re-thread it. That should be easier compared to removing the coupler.

I'm not good at welding neither, and I'd try to avoid it. Thanks to cmccosta's reminder though.
 

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
If you intend to drill through the plate in the female portion , you can get it done without removing the whole part from the bilge . Get a small size electric drill can do , check the spacing between the two diaphragm that can accommodate the drill . But to get it re- tap may be difficult as it is obstructed by the shaft , you have limit spacing for the taping action , use a box instead of a T bar may be useful. Worse come to worse , you can replace the strut by a bolt and nut , because the rear side of the female portion can be access easily and you can get the male section tighten by a box and spanner on each side . Good luck .
 
Sep 5, 2010
74
Yamaha 25 Hebe Heaven
Boffin you've pin-point all the problems that it might have indeed!

In fact I've tried drilling the hole w/o removing the female part, as I intended to drill it through together with the boat's fixing where the female part is bolted. I wanted to use nuts to fix the screw on the female part with the boat's fixing.

It failed as my 12V DC hand drill was to big to fit in between the bilge's fixings.

I guess if I can slide the female part up, and make the hole on the upward side (instead of left & right sides when bolted), the hand drill can do the job.

Anyway, I'll see if it works in the coming Sept!

Thanks again!
 

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
I am in doubt you can rotate the square shape female portion in 90 degree to make the hole at upward position. Need to check the width within the bilge. May be you can try to use a tubular type screwdriver as a low speed drill. It is far better than hand drill. The distance from the center of the strut to the edge of the shaft is less than the dia of the shaft (7/8", may be 3/4") or you can get an angle drill/ attachment to drill .
 
May 20, 2013
10
Yamaha 25 Macau
Regarding the drip-less seal systems, I'm considering to try to install one of those in October. I believe they will fit well.
The shaft diameter is 22mm. The shaft length between the log and the bilge is definitively long enough. The limitations I can find are the width of the bilge at the log area may not be enough for the bellow and some eventual pitting on the shaft may not allow watertightness.
 
Sep 5, 2010
74
Yamaha 25 Hebe Heaven
Good to know you're going to try the new drip-less system. Please let us know how it goes! Thx!
 

noname

.
Mar 10, 2014
2
Yamaha 25 Mk II Monkstown
Hi All,

Delighted to find this forum - I hope you are still checking in to answer my query here :)

I recently inherited a Y25 Mk II from a friend of the family - it has been standing in a yard for the last 2 seasons - and I've had it surveyed in the last few weeks as it is out of the water.

All in all, it is in good shape - so there aren't that many jobs to do before getting it back in the water.

However, as I can't tell the last time it has been done, I'd like to repack the shaft gland as a piece of preventative maintenance.

I'm comfortable enough as to how to do this based on the helpful posts on this forum - but I've noticed that the rubber hose aft of the gland is in poor condition - the rubber outer is gooey - probably de-vulcanising having sat in dirty/oily bilge water for a season or too, see photo.



Any suggestions as to how to deal with this?

Would the shaft have to be completely removed to replace this? (With necessary rebalancing afterward)

Is the shaft all one piece from gearbox to prop or is there a coupling along the way somewhere?

If I leave it alone and put it in the water - and it fails - how big of a problem is it liable to be? (Big I fear)

If I go to replace it - what kind of hose should I be using to replace it?

All input welcome!

Thanks,

Ray
 

Attachments

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
noname :

yes , you have to completely remove the shaft to replace this "rubber Tube ".

I used the hose with reforcement , similiar of those in the exhaust hose to replace . It haas been some 10 years , so far so good . It just serve for watertighness only , no strength applied on it .

The shaft is a one piece from the gear box couple to the pro., no join.
 

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
you may carry out a water test , fill up this compartment /bilge with water and see any leaking outside from the shaft coming out from the hull. To play saft , better get it replace , it is straight forward.
 

noname

.
Mar 10, 2014
2
Yamaha 25 Mk II Monkstown
Hi Boffin,

Thanks for the response - I've opted to repack the gland and to leave the rubber tube as is and float the boat to see if there are any other issues before undertaking a shaft removal - all going well, I'll leave the shaft removal until next year.

In the meantime - I'm wondering if there is a need/method to grease the shaft in the rubber tube area or indeed in the hanging mount outside and aft on the shaft.

I would have expected there to be some obvious grease nipples there if was intended to be greased.

Any thoughts?

Thanks,

Ray
 

Boffin

.
Aug 30, 2010
80
yahama 25 Hong Kong
There are 3 supporting points for the shaft in the Yahama 25, one is outside in the water --the cutless bearing , iit is lub. by the water . the second is the "house" where you put the shaft gland, the 3rd is a suspend rubber bearing close to the coupling to the gear box --that is the place you need to apply the grease. There is no grease nipples. disassemble the collar , slide it out , apply the grease and fix it back.
 
Sep 5, 2010
74
Yamaha 25 Hebe Heaven
Finally I've got it fixed by drilling through the stuffing box together with the supporting back-plate by using a angular drill adapter.


The back-plate supporting the stuffing box is fiberglass, so once I got through the bronze, it was easy to get through.

I use a smaller M6 screw and lock nut (i.e. nut with nylon ring) to fix it. After fix it, my bilge had become much drier!

My next fix will be replacing the cutlass bearing.

I am in doubt you can rotate the square shape female portion in 90 degree to make the hole at upward position. Need to check the width within the bilge. May be you can try to use a tubular type screwdriver as a low speed drill. It is far better than hand drill. The distance from the center of the strut to the edge of the shaft is less than the dia of the shaft (7/8", may be 3/4") or you can get an angle drill/ attachment to drill .