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View Full Version : YSM8 - Rebuild or Repair



78dave
06-25-2014, 08:00 AM
OK, took a YSM8 out of an AMF boat because it was leaking motor oil between the crankcase and transmission. Further inspection revealed the flywheel end bearing had worn out of round and lightly scored the crankshaft. I took the motor to a precision machine shop and they felt the crank was not bad and could be polished out. Will have to wait to determine if the crank is within tolerances. I took the crank out and thin the timing gear end bearing should be replaced and might as well replace the rod bearing. So in the end I have about $350 in the main bearing, and $200 in the two other bearing plus a couple of gasket and a seal. So figure maybe $700 in parts.

The question to all of you is part it out or fix it and try to sell it. It has the original alternator, electric starter, crank will be good and they do not make these anymore, and lots of other parts on the motor. I also wondered if someone really wanted this motor I could fix it and sell it or even let them buy it and buy the parts and I fix it for them. I am in central Missouri, but could deliver within a couple hundred miles to meet someone.

My concern is as I get into this I either overlook the top-end and just do the crank or go all out and keep pouring money into it. Tappets, valve stems, rings and other things just have to have wear too. The timing gear end bearing is worn so I have think other parts are worn too. The engine ran great though until it started knocking as the big main bearing was going out.

Thoughts?

Figment
06-25-2014, 10:29 AM
Part it out or sell it as-is.

Unless, of course, you're just looking for a project to play with and don't really care about making any money for your time.

Andrew2
06-25-2014, 12:27 PM
Part it out or sell it as-is.

Unless, of course, you're just looking for a project to play with and don't really care about making any money for your time.

Same here. It is an old engine that has spares problems. You rebuild it at some cost (quite a lot for a proper job) and you are selling an old engine. Are you prepared to offer a warranty?
Fact is, only an enthusiast would buy it and would prefere it as is. Guy in UK is looking for a c/head, but might have found one. That's your market.

Funnily enough, I just fixed a Ford 1.6D that had the same problem. Not the bearing, just the seal and some gaskets + the fresh drive plate. Parts are by return of post for a 12 yr old marinisation of an auto unit, so easy. Not so with an older Yanmar.
I saw a V twin Yanmar on the dockside recently and thought 'That looks interesting, maybe I should ask....' Then slapped my wrist and walked on. I like old engines, but ya gotta be realistic.

webfoot
06-25-2014, 08:25 PM
I have one in my boat and find it is had to get parts, reliable engine though.