Yanmar YSE8 "slippage"

[OneidaLakeSailor]

A related question - I have a YSE8 in my Irwin 10/4 - what kind of torque should the clutch be able to handle?

The reason I ask - I've been having some trouble getting propulsion through the weed patches between my marina and the nice sailing grounds.

Not sure if it's straight-up fouling or if the clutch is weak.

I tested the clutch this morning- secured the prop end with a pipe wrench, padded and braced, and grabbed the nut on the crankshaft with visegrips and another pipe wrench, and with the clutch engaged, proceeded to torque it manually until I could slip it. It slipped equally in forward and reverse, best guess at around 80 ft-lbs of torque ( with my finely calibrated arm

This seems that it ought to be enough torque to propel this boat at speed.

I have no idea what the torque output of a 7hp engine ought to be, nor how much torque one of these clutches is specified to be able to transmit.

I did push against the docking lines this morning and it seemed plenty strong - and I have a pruner now to get rid of weeds... but I'd love to know what the clutch should be able to sustain.

Thanks!

[mitiempo]

I'm not sure how much torque the YSE8 has but it's a pretty small motor for your boat. The 10/4 is a foot wider than my CS27 and almost 1000 lbs heavier. I have a YSE8 as well and most CS27 owners consider it a bit of a lightweight.
The propeller will make a difference as well. Do you really think the clutch is slipping or does the boat just seem underpowered?

[OneidaLakeSailor]

I do think that on paper it's a tad underpowered for the weight of the boat - but when everything is clean it will run just shy of six knots - and do it all day long. That was bringing her down to the lake, on the canal. No weeds there! That being nearly hull speed, I probably shouldn't expect more.

It also pushed us into four footers out the inlet heading onto Lake Ontario from Sodus Bay for the delivery sail bringing her home.

When it does start to get caught in the weeds I can't tell if the clutch is slipping and the prop stuck, or if the prop is still turning but dragging a bale of weeds with it, and all that vegetation and the weeds obstructing water to and from the prop. Either way, that little diesel is struggling with the load.

That's going to be the next test - to go get it good and fouled and watch the propshaft between the transmission and the thru-hull.

Then, go swimming, test my weed removal method - brand new fiskars tree pruner and a snorkel for me- and see if it picks right back up again.

And if it's the clutch and I find out I have to pull the engine to get at said clutch, I may bag it, hang a nice fresh 9.9 off the back of her and call it a day. It matches my expertise better since I know gas engines well but not diesels, and even though the simplicity of a diesel should give better reliability on paper, I fear the age factor is hurting us in that regard.

I looked up some more of my hardcopy literature, and I can't find torque specs either.

Have you had any trouble on your YSE8?
Done any clutch work on it?

Thanks for responding - I appreciate it.

Andy
In the marina pending good conditions for a test day...

[ffiill]

If these gearboxes are like the small mechanical Hurth ZFs then what happens is that the little clutch plates by locking the lay shaft cause the necessary gears to dead lock together by means of a surrounding cylinder which throws forward when the layshaft is locked.
Similar to mechanical diff locks on 4x4s
The motive behind this system is so you can use very little force to operate the box.
You need to see one apart to grasp this operation(as I once did)
Neat but if the clutch plates wear out! - this is usually due to thrust bearing wear and too small a box on too big an engine.!

[okawbow]

I have a YSE8 in my 1976 Bristol 24. I was told to only use straight 30wt oil in the engine and transmission. However, when I got my boat a few years back, the PO was using mobil 1 synthetic oil in the transmission, and straight 30w in the engine. I have stayed with Mobil 1 in the transmission, and have motored over 1000 miles with no problems. My Bristol weighs over 6000 lbs loaded, and I can motor at hull speed easily.

I'm not suggesting you try Mobil 1, but it seems to work in my rig.

[OneidaLakeSailor]

A post mortem on all this. First, thanks to all who replied.

I went back up to test it - waited for a day with light wind out of the north just to make sure I could get back easily on the sails.

It was all due to the weeds. Once I had it clean, it ran right up to five knots like nothing.

Looks like I'll need to be swimming more often in the future....

Andy
Irwin 10/4 on Oneida Lake in Upstate NY - 16 mile downhill run today to where it will be pulled out to sleep for the winter...

[mbalka]

Seaweavermarine:

I have a YSM8 that is doing the exact same thing to me in a Watkins 27. Where did you procure the transmission manual? I have the 3:1 reduction gearbox on my engine, but it is a Kanzaki and I will most likely need to rebuild/replace the cones, but cannot find a copy of the manual for the xmsn with part numbers. Any help you could render is greatly appreciated.


Mike Balka
S/V No Cents
Lake Norman, NC

[paytman]

Hello again, bought a used Yanmar 3HM35 with the Kanzaki KBW 10 to swap out the transmissions, as mine (just replaced 4-5 years ago) is slipping again.
Looks straight forward to swap, save for some alignment, but how difficult to change the damper plate?
Also, how can you tell if the damper plate is worn out?
And, a request, anyone have an exploded view diagram of this type of transmission, more for curiosity sake.
Robert
LUNA P36-2 #110

[Northeaster]

For those with slipping Kanzaki transmission, like on 1GM, 2GM. I had this on my 2GM. Was able to take trannie apart and "lap" the drive cones - rough up the surface slightly with valve lapping / grinding compound. Try this before uying a new one!! mzine has worked well for 3-4 years since doing this. The mating surfaces of the cone clutch csn become glazed, and gets worse once it slipps more. Of course, if the cone is worn out, no amount of laping will work, but it is worth a try. Put some alpping compound between the 2 surfaces and by hand, rotate and push the two surfaces together. It only takes a couple of minutes, perhaps making a few complete rotations, to take off the shine.. You don't want to grind off an appreciable amount of the cone..just scuff up the surfaces. Do the fwd and rev surfaces.

By the way, the trannie should have a noticable clunk as i is shifted into gear. If not, the cones are likely slipping somewhat.

[deltasig]

Couple of questions since I have the problem with the forward gear slipping but the reverse works well all the time (engaging with the characteristic "clunk").
Do you recommend using new seals for the transmission (front and back) after dismounting?
Is the glazing visible? how I'd know that I lapped the cone enough?
I have only 750 hrs engine run time since new (mostly sailing for 14 years); any ideas why the cone would be glazed?