YSM12 Cylinder Liner

[Bud22569]

I am planning to replace the cylinder liner in my YSM12 as part of a rebuild. I have not removed the old cylinder liner yet. The Yanmar shop manual is confusing about the construction of the YSM12 cylinder liner. The detailed drawings indicate that the outside wall of the cyliner liner is smooth. The instructions specific to the cylinder liner wall indicate that there are two grooves machined for the O-ring seals to seat. The liner that I have in my hand has no grooves for the O-rings to seal, it is smooth as indicated in the detailed drawings.

My question is: have any of you replaced a liner in a YSM12? If so, are the grooves for the O-rings machined into the cylinder liner or into the engine block?

The shop manual tells you to install the O-rings on the cylinder liner before sliding the liner into the block. It would appear to me that you would need to install the O-rings into the block before sliding in the liner.

Any lessons learned on a YSM12 cylinder liner replacement would be greatly appreciated.

 

[Rick2413]

If memory serves the 2 O ring slots are in the block(hopefully my pic is attached) I used olive oil as a lubricate to slide the new liner in. Some say olive oil does not harm the rubber O rings as some petroleum products do.(old wives tale?????) The old liner was a bit sticky getting out because of the raw water crud in the cooling chamber was encrusted on the liner.

 

[JoeD]

Liner

O Rings are in the block. A tip on removing cylinder, Is pack with ice with before pushing out. We used dry ice. Let set for half hour. Will come out very easy. If you use dry ice please be very careful you can remove your skin very easy. Good luck.

 

[Bud22569]

Thank you both. This is exactly the type of information I was looking for. Did you have a puller built for the job or were you able to find a puller on the market that did the job?

 

[Rob19574]

tech support at Mack Boring - Yanmar

Also you should try the tech-support folks at Mack Boring - they rep all Yanmar marine engines, supplies and tech support. They have a really knowledgeable staff there that know these engines inside and out and will be extremely helpful. I think the number is 866.526.9717 - ask for tech support for Yanmar Marine.

Good luck - Rob

 

[Hermit Scott]

Liner YSM

If you are planning on taking the crank out, you can knock the old liner out from the back side. There may be alot of corrosion in the water jacket. Mine was so bad all the ports to the head were clogged except 2 small pencil sized holes. A couple of tips for the reinstall; measure the diameter of the block when you take out the liner, It's like 4"or 5". Go buy a wire wheel 1/2" oversized. Then run that into the block attached to a drill to clean out the ledge that the top of the cylinder sits on and the grooves that are in the block that the O-rings sit in. I used water proof marine grease for trailer wheel bearings and coated the liner the rings and especially the ledge area to help seal when assembled. Install the O-rings in the block with plenty of grease all over to help them stick in place. Stick your left hand in the block to feel the Orings and use your right hand to slide the liner in to place. Use grease on everything you assemble and change the oil after the first 30minutes of breakin at a low idle then change the oil after 2 hours more of break in at a high idle to get all the assembly grease and anything else out.