Yanmar SD20 Sail Drive Caution

[GordMay]

mazagran:
Ingenious !!!
And welcome aboard.

[captjohn360]

ok mazagran how many times have you done this? in theory it sounds great . but if there is any sea water in the threads or bottom of the sail drive it seems you are asking for trouble. jt

[Strygaldwir]

I read about someone else who had a SD20 on their 48 foot cat. He was stuck in the South Pacific when he developed a leak in his seal. He was unable to find a place that had facilities for hauling his 24 foot beam boat. He used a very similar technique. He did not have a plug, so he just pumped oil in the top until it started coming out of the bottom of the sail drive. I am not certain whether he used plastic to contain the old oil or not. Anyway it is not something I try here in the US. Spilling oil can be VERY costly

Cheers and thanks

Keith

[h2oman]

I'm a newbie to this forum but have had some experience with SD20s. Trust me - if the drive oil is milky - get it taken of ASAP.
Our starboard drive had milky oil as a result of fishing line tearing up the seals. There's only one option - the boat will need to get pulled to change the seals.

Sure wish that there was a line cutter available that would work on SD20s.

Changing the drive oil without having to pull the boat sounds really neat. Has anyone else tried this procedure?

[mazagran]

do not know if somebody still reads this thread, ok, how many times I did change oil in the water? Twice only, when the oil of one drive was a little milky and I was in a hurry to change it. Usualy I beached the cat and changed the oil using a bucket. Was always big fun as the tide in the tropics (Far East) is about 3' or 4' and we mostly had to dig a hole in the sand to get the bucket below the drives and hold them down against the sea.

Well next boat will have shaft drives, I do not trust those underwater bearings on the saildrive any more. The upper diaphragm was never a problem, but again I was scared all the time after three years as the manual requested a change, but I never did. The underbody cover of the saildrive hole was a problem, Sikaflex and whatever else always came loose until I screwed it with a stainless ribbon.

My saildrives never let me down, but never made me happy too, will see what to say about the "drippless seals".

[Sonosailor]

How hard is it to renew the seals in an SD20 (on dry land)? What parts do you need and what tools? I brought Cat Tales up the coast, replacing the top 1 litre of oil in the starboard saildrive every day and a half.

Also, what brands and specs would you consider a superior oil?

[Alan Wheeler]

Can't help you with the saildrive. But for the oil, maintain the specified viscosity. I do however, recommend a full synthetic. This is because it still maintains a high EP (elastopolymer) strength IF water does get in. A mineral oil mixes with water very quickly and breaks down, loosing the EP strenght and loosing it's ability to protect parts from corrosion.
Personly I have had great results with Amsoil, but any "good" synthetic should do the job. I would however, stick to the known brands like Sheel, Caltex Castrol etc etc. Don't go for any of the "boutique" producers especially if they say it was developed by NASA or anything to do with "Space technology". That is usually a total Crock.

[windthief]

The premise by Yanmar is that there is a reccomendation for a boat to be pulled out of the water anually. For winter or here in the warmer regons hauling out to apply anti fouling and so forth. My point being Yanmar ASSUMED we all do this and to do the said service wouldn't be an issue.

If it's not done and logged and there becomes a warranty issue Yanmar will shoot it down immediatly.

Sorry,

[cchesley]

I have an additional issue with these units.... the fairing rubber boot. (Not the rubber seal which is an integral item. My boot which fairs the saildrive with the hull has separated from the hull. I'm told that it is not a critical issue but it does represent additional drag at the least an possible source of problems down the line, not the least of which is marine growth etc etc. Anyone else experience this? What do you/have you used to 'glue' the rubber to the underside of the hull?

[seafox]

I have had three saildrives now. Ados contact glue is the best thing for gluing on the boot. Rough up the boot with some course sandpaper then use some acetone to clean it. Paint a couple of coats of Ados F3 and let it dry completely. Clean the hull (get all the old glue off) with the paper and acetone and paint a coat of Ados F3 on that. Once it is dry pull the boot over the saildrive (make sure the drain hole is in the front) and position it where you want it. Use a small roller to press the boot on. You can also use a heat gun (hold it far back though) to help the two sides contact. My first boot had been on for years and was very hard to take off. We replaced two motors in the last year and the boot that had been on for a year was very well stuck with the Ados F3.

[SeaKing]

I recently bought a used cat with twin Yanmars and the SD20's. I have been thinking about the issue of changing the oil as I am over the 100 hours. The oil looks good and we will haul for the winter soon so I am just waiting for that.

But, an owner on the Voyage Owners association Bullentin board has done something I want to try. He has fitted a reservoir above the waterline with a tube attached to a small fitting on the fill cap on the top of the SD20. This creates a positive pressure that if a lower seal does fail water will not come in. Also easy to check oil levels visibly. Since he installed that he has had no problems.

It is in the thread below along with other discussions about the saildrives
http://groups.msn.com/VoyageYachtOwn...48305502090099

[Strygaldwir]

Seafox; I recently checked my saildrive bottom gasket. One of the gaskets I'd used starboard and screws to hold it down. The other, I'd used 4200. (Hey, that's what the yanmar guy working on the boat next to me was using!:-) ) The glued gasket has come up. I think I'll go back to securing the edges with starboard.

Keith

[seafox]

Don't know if you have Ados F3 where you are. It is a syrupy amber coloured contact adhesive. What they use for fixing shoes and that type of stuff. When you need to get the boot off it is stuck very hard and just about tears the boot.

[windthief]

Using bellows adheasive by Mercruiser or Volvo works well also.

[Tellie]

Originally Posted by SeaKing

I recently bought a used cat with twin Yanmars and the SD20's. I have been thinking about the issue of changing the oil as I am over the 100 hours. The oil looks good and we will haul for the winter soon so I am just waiting for that.

But, an owner on the Voyage Owners association Bullentin board has done something I want to try. He has fitted a reservoir above the waterline with a tube attached to a small fitting on the fill cap on the top of the SD20. This creates a positive pressure that if a lower seal does fail water will not come in. Also easy to check oil levels visibly. Since he installed that he has had no problems.

It is in the thread below along with other discussions about the saildrives
Voyage Yacht Owners Association

Now THAT'S an interesting idea. Like Sully said I experiance that Pffft each time I check the saildrive oil. Certainly it's a pressure build up from heat. So logically heating and cooling off positive pressure, negative pressure could affect the seals. My Yanmar guys are really great and won't give you the Yanmar line of just buy the new part and be sure. I'll run this idea of a resvoir by them and get heir input.