Yanmar SD40 vs. Yanmar SD50

[casar]

Hi, I am Cas from Germany near the city of Cologne.
I have just registered and it is my first post here.
My boat is a 37 foot long aluminum trawler. It is a self-built boat that I bought three years ago. It has been extended and fitted with a Yanmar 4JH4e engine with a Saildrive SD50. It runs very well and I'm generally very happy with it.
And that brings us to my concern: The engine and saildrive have now completed around 2300 operating hours and the saildrive is starting to cause problems (bearing damage, probably propeller shaft). I also have water in the gear oil. The clutch isn't causing any problems at all, as I don't experience any wear in the neutral position because I'm not sailing.
Now I can get a completely new SD40 at a reasonable price, which should also fit plug and play. What exactly are the differences and is this a good idea?
Many thanks
Cas

[skipperpete]

Hi Cas, welcome to the forum. The differences between the SD50 and SD40 saildrives are surprisingly few, the cone clutches are the same, as are almost all the other internals.... I think there’s a difference in the lower leg but would need to browse the parts catalogue to confirm that. The really significant difference is the size of the mounting flange, the SD40 is SAE#5 , the 50 is SAE #4 so there’s a problem right there. The 50’s also use Quicksilver gear oil but I guess you already have that. It’s very unusual to see a Saildrive installed on a trawler hull where the engine is always needed, a Saildrive is not well suited to continuous duty on a motorboat, particularly an SD50.

[casar]

Hi Pete,
according to my Service manual both are SAE5. Only the -4T ones (40&50) have SAE4.

I am wondering about the difference not just between SD40 and 50, also between SD40-1 to -4, -4 was the last redesign of the SD40.

the boat runs with the SD50 more than 20 years and 2300h without any service apart of the oil-change. And the preowner never had used the expensive quicksilver stuff. So I think it was not a bad idea at all.

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Originally Posted by casar

Hi, I am Cas from Germany near the city of Cologne.
I have just registered and it is my first post here.
My boat is a 37 foot long aluminum trawler. It is a self-built boat that I bought three years ago. It has been extended and fitted with a Yanmar 4JH4e engine with a Saildrive SD50. It runs very well and I'm generally very happy with it.
And that brings us to my concern: The engine and saildrive have now completed around 2300 operating hours and the saildrive is starting to cause problems (bearing damage, probably propeller shaft). I also have water in the gear oil. The clutch isn't causing any problems at all, as I don't experience any wear in the neutral position because I'm not sailing.
Now I can get a completely new SD40 at a reasonable price, which should also fit plug and play. What exactly are the differences and is this a good idea?
Many thanks
Cas

clutch problem is on sd 40/50 gve more money and buy sd60.
for laping clutch in croatia you must wait 50-150 days

but if you pay onder 2000€ is ok use 500-1000 hour think later. but 2300 hour and problem something is wrong with installation or skipper.

[casar]

It is a motorboat not a sailing boat. The clutch problem results from sailing in neutral gear and the prop rotates all the time. But even for that problem you can upgrade the clutch.
So much for my research.

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Originally Posted by casar

It is a motorboat not a sailing boat. The clutch problem results from sailing in neutral gear and the prop rotates all the time. But even for that problem you can upgrade the clutch.
So much for my research.

wrong and not important info for now ,also charter sailboat is motor boat but with sail for nice looking. i dont calculate power sizing ,you calculate HP when bulid your boat.

yanmar call SD 40/50 light use under 50 hour low quality saildrive but last 500-1000 hour. SD -60 is pro version havy duty.

charter boat usually make 500-600 hour by season how many annual hour you do. this is also important info .for that reason almost all charter company when recive new boat change saildrive from sd/50 to sd60

PS.
YAnnmar od sd-40/50 saildrive like france ing designer make car.
for Exchange oil filter must remove light,cooling system and sometime engine must go out.

or for sea impeller you must first remove alternator and cooling system. but dont make small door on this side. Or cuting bed. to come close to saildrive on lot jeannau sailing boat.

Ps. before 2 year we have on cat 6 hour old problem cone clutch sd 50. later on 55 hour in portugal again. now imagine what i think yanmar sd 50

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but for new sd-40 1200€ is fer price
https://www.kleinanzeigen.de/s-anzei...00437-211-2575

[casar]

What can I say? My boat make 2300h with one clutch and without any service. Why should I change?

Yes, I know that add. Because of that I ask for a SD40 instead of a SD50.

[skipperpete]

So is your existing Saildrive a SD50T? There’s a guy on this forum, username “Brickwede” who posted some really sensible information about SD50’s and how to keep them alive, his first name is Jochen, hit the search button and browse Brickwede posts. He also sees no need to use Quicksilver gear oil but back when the 40’s and 50’s were still available from Yanmar, not using the recommended oil raised issues re warranty claims. Nice boat by the way, when I read “self built” I feared the worst but she looks like a sturdy well built vessel from that photo.

[casar]

Yepp, I am already in contact with Jochen Brickwede. He has developed his own upgrade kit for the clutch and many more. He Aanalysed the clutch problem as well.
My SD50 is a standard one. So a SAE5, like the SD40.

Yes, she is well build. It was love at first sight. It is made from alumnium and with quality parts.

[casar]

I would still like to know the differences between the SD50 and SD40 in order to decide whether I should/can exchange my defective SD50 for an SD40.
I am grateful for any information.
Cas

[more]

Originally Posted by casar

I would still like to know the differences between the SD50 and SD40 in order to decide whether I should/can exchange my defective SD50 for an SD40.
I am grateful for any information.
Cas

download and reed https://www.autorepairmanuals.ws/arm...-manual.79947/

[casar]

I have read that but did not give me the answers I asked for.

I have researched that the spare parts are all the same except for the housings.
Is it that simpel? Are the old housings not good?
Then I have to ask myself why Yanmar is making a new model out of it. For what?

[johnmyjo]

saildrives@yahoo.com
Ask these guys. They know everything there is to Know re. SD40. SD 50

[skipperpete]

I think your best path is a long read of the parts manual rather than the repair manual, this way you can compare the actual part numbers to see what might have changed between the releases. The only tricky bit is if the part....... maybe a propeller shaft ..... is dimensionally identical but a different higher quality alloy steel. Your engines output is at the extreme upper limit of what an SD 50 can transmit so it’s not unreasonable to expect better quality metals at the weaker points, often we use an Aquamet shaft if a more powerful engine is installed, maybe Yanmar just did an upgrade to hi tensile shafts. I’m happy that you found Brickwede, I’m sure he can reliably inform your decision re the SD40.