Yanmar ysb12

Mark F

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May 20, 2017
2
s2 9.2 Holland MIchigan
I purchased a project s2 9.2a (sat for 3 years) which has a ysb12 engine aboard and as I am new to diesel inboards, I have many basic questions. I have found some info on the web, but I would like some confirmation. I did get the engine to start, but shut it off right away. I have purged all the fuel lines, re primed the system with fresh fuel and it started up quite well. Now my next step is to change the fluids. I am planning on using Rotella T 15w 40 for the engine, but I am unclear as to what fluid goes into the transmission and how much. Also I am unclear as to drain the engine and transmission. I know that I can draw it out from the fill hole, but I am hoping there is a easier way. I have not been able to locate a service manual to download or purchase, if someone has some ideas. Thanks.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
Also I am unclear as to drain the engine and transmission. I know that I can draw it out from the fill hole, but I am hoping there is a easier way..
Get your self a vacuum oil extractor like http://www.defender.com/product3.js...mp-5-liter&path=-1|2285701|2349116&id=2034743 -- the engine will either have the drain plug re-routed to just above the oil pan - or you suck it out of the dip stick hole. Be sure and warm up the engine for a minute or two (not too hot) so the oil is extracted easier. Transmission oil usually comes out the fill hole (usually ATF or 30wt depending on trans).

Don't go cheap and get a pump - they are just an oily mess.

Les
 

RAD88

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Dec 15, 2008
163
Hunter 30 Glen Cove, NY
I have an original service manual and a copy of the operations manual . PM me if interested.
The service manual is for the YSE engine but its all pretty much the same powerplant. I have never seen a manual for the YSB.
One way to remove the oil or tranny fluid is to pump it out the fill holes. If you can access the drain tube on the port side of the engine you can pump the engine oil out there also.
Are you planning to run the engine in cold weather? If not use Rotella 30 weight straight. This is a hard working little engine and needs the heavy oil.
 

dLj

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Mar 23, 2017
3,373
Belliure 41 Sailing back to the Chesapeake
I also have an early Hunter with a YS something engine in it. I don't know yet what engine it has, but I have been collecting as many documents from various places as much as I can. Let me try to post copies here.

Hmm, got two up, let me post these, just got an error message saying one was too large...

dj
 

Attachments

dLj

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Mar 23, 2017
3,373
Belliure 41 Sailing back to the Chesapeake
Let me try a separate post - ah - just realized there is a maximum size of 2.4 megs - I have several that are too large. PM me to see if I can send them to you some other way. One of these is listed as "Yanmar - YSE - YSB Service Manual.pdf". Might be of interest.

dj
 

dLj

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Mar 23, 2017
3,373
Belliure 41 Sailing back to the Chesapeake
I was thinking about these old engines and what I may encounter in the not distant future in my own rebuild project. So researching what it takes to repower or rebuild, the rebuild side for me always houses a lot of interest. I simply like old engines that have no electronics, are completely mechanical and can be started by hand. I haven't seen modern engines that have all that, although if anyone knows of a modern engine meeting those three requirements, I'd love to hear.

Thinking about what I've read on these old Yanmar engines and how they vibrate a lot lead me to look into balancing systems for all the rotating components in an engine. So one thing lead to another and I ran into this web site:

http://jandm-machine.com/marine.html

They actually have an Atomic 4 engine that was rebuilt to withstand raw seawater cooling. They appear to have all the balancing equipment for dynamic balancing of both individual components and the system as a whole. Made me think that there may be rebuild options out there that could be quite successful to pursue, should the need arise...

Just some food for thought.

dj