Yanmar SD50 Saildrives - Have the Cone Clutch Problems Been Solved ?

[paulrack]

Have the newer SD50 sail drives had their issues with the cone clutch's resolved?

[Captain Bill]

I don't know how they could have them solved. According to the parts manual I have they use all the same parts in the cone clutch. That is all SD40 and SD50 models use the exact same parts in the cone clutch. My understanding is that the only change has been in the owners manual which now calls for more maintenance adjustment, primarily by frequent lapping of the clutch surfaces.

[Kiwikat]

Are there any updates on this? Our local Yanmar agent has just advised us to upgrade to SD50's but from what I have read here and in the http://www.cruisersforum.com/forums/...tch-19413.html thread I remain sceptical at best. He was referring to the needle bearings rather than the clutch cones but I was rather hoping for an overall solution as we have just started to experience the odd slip on the saildrive where the needle bearing is still ok.

Cheers
Lisa

[Srah 1953]

I have an SD50. What is involved in the lapping of the clutch surfaces?

[Panache5000]

I have two year old SD50's The one does not engage in forward or revese when I put it into gear, I have to either blip the throttle or try again. Once it does engage in gear however, it does not slip. Is this a case of having to lap the cones?? Would appreciat advice.

[Sunnygirl]

I was looking for the old thread and found this one. The problem is caused thru use and excasserbated by things e.g. when engaging into gear, a heavy prop, too fast off the mark etc. The cones glaze and it's quickly downhill from there - losing drive. Getting the relevant gear cluster out is not hard and it can be remedied without new parts. Once out, undoing the nut that holds the cluster together is hard, you need a die grinder to cut out the locking indent on the top nut. The nut is then ridiculuously tight. So you need to have a workshop vice and soft jaws, die grinder and a 27mm socket spanner. There are some helpful sites describing this, but, they make comments like 'remove the nut with a wrench'. Evidently there is piece missing in their experience of doing this job compared to mine. Bite the bullet, lap your cones - or get someone to do it for you the first time and the issue will become less mystical! Not a big issue, no more than changing the timing belt in a modern engine is.

[Srah 1953]

Originally Posted by Sunnygirl

I was looking for the old thread and found this one. The problem is caused thru use and excasserbated by things e.g. when engaging into gear, a heavy prop, too fast off the mark etc. The cones glaze and it's quickly downhill from there - losing drive. Getting the relevant gear cluster out is not hard and it can be remedied without new parts. Once out, undoing the nut that holds the cluster together is hard, you need a die grinder to cut out the locking indent on the top nut. The nut is then ridiculuously tight. So you need to have a workshop vice and soft jaws, die grinder and a 27mm socket spanner. There are some helpful sites describing this, but, they make comments like 'remove the nut with a wrench'. Evidently there is piece missing in their experience of doing this job compared to mine. Bite the bullet, lap your cones - or get someone to do it for you the first time and the issue will become less mystical! Not a big issue, no more than changing the timing belt in a modern engine is.

Sorry for being an idiot, but I'd still like to know what "lapping the cones" means.
Thanks anybody

[colemj]

I would not consider having to lap a cone clutch every year or so "not a big issue" or standard maintenance.

To do so would be to support and encourage inadequate engineering.

Mark

[Sunnygirl]

Cheers Mark, I agree, it seems that the cones will run up into the 1000's of hours and maybe never lose grip. I'f anything excasserbates glazing the failure will happen sooner. e.g. I got a rope wrapped on a prop, 6 months later that system needed lapping. Heavy props, fast gear changes etc will reduce the re-lapping interval. I was taught to use rudder thrust to bring my cat sideways into a berth by rapid reverse / forward cycling on both engines, probably wouldn't be a great life extender. Consider also the Gori folding prop chshions, some people chew them up fast and others don't. My guess is that if you clunk those out fast you'll also need to re-lap your cones faster too. Same way some people burn out clutch plates faster than others in manual cars or trucks.

[Sunnygirl]

Cone school!! It's scarry when the boat won't go into gear. The cones are the same as a clutch plate in a manual transmission car. You can 'play' the car clutch to take off smooth, also the wear out slowly. Cones clutches are either in or out, go or no-go. Outboards generally use dog clutches -in or out too. The difference between dogs and cones is that dogs engage lie a knife and a fork - bang! Cones can slip momentarily or under extreme jamming forces. That's handy if you get a rope wrapped on your prop. Also they are nice and quiet when engaged gently. Correct me, but, I think SD20's are dog clutches, bang! This conical male/female clutch is very civilized, but, it can slip - without warning. Lapping is a process of deglazing the brass cone and cup using a very fine abrasive. The result is that the friction re-energizes the clutch action. Go gently on the engagements and you'll be fine.

[Srah 1953]

Originally Posted by Sunnygirl

Cone school!! It's scarry when the boat won't go into gear. The cones are the same as a clutch plate in a manual transmission car. You can 'play' the car clutch to take off smooth, also the wear out slowly. Cones clutches are either in or out, go or no-go. Outboards generally use dog clutches -in or out too. The difference between dogs and cones is that dogs engage lie a knife and a fork - bang! Cones can slip momentarily or under extreme jamming forces. That's handy if you get a rope wrapped on your prop. Also they are nice and quiet when engaged gently. Correct me, but, I think SD20's are dog clutches, bang! This conical male/female clutch is very civilized, but, it can slip - without warning. Lapping is a process of deglazing the brass cone and cup using a very fine abrasive. The result is that the friction re-energizes the clutch action. Go gently on the engagements and you'll be fine.

Thank you Sunnygirl

[itamary]

Srah
I can see that you are online, and I would be happy to know if there is anything new concerning the sd50 slippage. any remedy?

[Srah 1953]

Originally Posted by itamary

Srah
I can see that you are online, and I would be happy to know if there is anything new concerning the sd50 slippage. any remedy?

You are asking the wrong person, try one of the other respondents to this thread.
Kind regards
Srah

[Fantazia]

Finding out the problem exists before chasing folding props etc is problem one. Then on finding out you've only got one engine in Noumea and need to get back to Oz is problem 2. Getting someone qualified and willing to fix it there leads to ultimate problems with Yanmar itself in Australia, and your warranty.
I've now been two years with this grief as the leg is now working fine, but the oil in the leg is frothing up on long passages, so much so that when you open the oil filler it flows across the floor of the engine room. This overflow is not cloudy or milky so it's not water, Has anyone else seen this with another Yanmar SD50 leg? FYI Yanmar are now telling me this is my problem as in the ensuing 1.3 years the warranty has expired, catch 22. Watch out for these guys, they don't tell you about the design fault in the first place and then don't want to help you in the second instant. maybe they could do something about it all in the build stage.

[Sunnygirl]

The recommended oil is Quicksilver / mercruiser / mercury. It's the blue oil. It's got an addiive which emulsifies water. Car gear box oil is the same spec but without that additive. When the oil gets hot the water will increase in vapour pressure and foam, maybe even boil. Even though the oil is not cloudy it may still have oil. Did you ever have a diagnosed seal problem? The SD20 is notorious for getting water up thru the lower seals. The SD 50 is a better leg.
You'll have to change the oil. maybe change it a few times, because it's hard to det it it all out unless the boat is on the hard. I'd use car gear box oil - EP90. it's a fraction of the quicksilver price.
Deglazing the cones is a quick job if yu know how. The hardest part is undoing the castle nut on top of the gear cluster, you need a big vice and socket set. Yanmar do it up over-tight. Otherwise you could do it on board.