Replacing SD40 with SD50

[claire]

After a series of troubles with one of our SD40s, and knowing there is more in store if we keep it, even though it is only 5 years old and around 1000h, we are biting the bullet and ordered a new SD50 to replace it.
The installation will take place in a yard in Thailand where we have never been before and we are unsure about the competence/experience of the local mechanic(s).
We would appreciate any useful tip from people who did the same operation: pics, descriptions, warnings. Example of questions: do we have to move the engine to depose the SD40? why? Is it tricky to "engage" or "fit" the new SD50 with the existing 3JH4 engine? Should we continue using the saildrive sea water intake, or should we just let it get stuck shut-off and install a thruhull for the engine cooling (as we know that yanmar saildrive sea water valves always get stuck and won't close down the road)?

Thank in advance for all the feedback.

[GordMay]

I suppose you may already have it (or will be getting it), but if not
➥ www.ekstrom.fi/index.php?doc_id=38.pdf

Good luck!

[tpoffen]

Claire (or anyone else who has experienced replacing SD40 with SD50 saildrive)...

How is your SD50 behaving? Any regrets? Anything we should look out for during the install or maintenance? We are in the midst of a haulout for bottom job and saildrive service and just found out that one of our SD40's is ready to be replaced. Eager to hear any advice on the matter.

Thanks,

Tom

new owner of 2001 FP46 Bahia, now called Compass Rose

[claire]

Actually, the replacement was simple and without surprise. The engine was moved just a little.
We installed a separate water intake and are very glad we did: we can now open and close as well as filter: we found debris of plastic bags in the heat exchanger of the other engine that still gets water from the saildrive. Also, the water tap on the SD50 is as bad as the one on the SD40: it gets stuck in less than 6 months.
Are we happy about the change? not particularly, but we had no choice, the old SD40 had taken in water massively through a bolt broken (and hidden) by an incompetent mechanic in Florida. The SD50 is basically the same as the SD40: a bad piece of mechanic from Yanmar; we still expect it to slip anytime after 600 hours which we have just reached.
The only visible improvement is the easier and quicker way to pour new oil through the bigger opening. As for the slipping, we learned a lot about the innards of the SD after the change: we completely dismounted the old SD40 and kept all the spare parts from it we might need in the future. That is probably the best advice we can give to anybody doing the same. So when, a few months later, our remaining SD40 started slipping, we bit the bullet and went through the whole lapping thing by ourselves.

[tpoffen]

Claire, thank you for the quick reply. By the way, where did you install the separate water strainer?

I have a lot more questions for you that are not related to this thread. I'll send you a private message.

Tom