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Re: Rebuilding a Yanmar YSM-12 using YSB head
Cause of the Failure isn't for sure other than it is an Old motor (mid 70's) that has an unknown number of hours on it and clearly has been overheated at lease once (I know that a year ago the impeller on the water pump when when someone else was using it and although they say they shut it down right away who really knows.) Needless to say the motor has had low copression for years and has just been getting worse with harder and harder starting. I knew this was going to be the final season before a rebuild but she finally just wouldn't even start anymore. When it finally gave up the ghost we found a cracked head bent and sticky Valves, badly scored piston and sleeve, Worn out bearing etc. There could have been any number of reasons for the final failure but that doesn't matter. It needs to be rebuilt or replaced. Yanmar does not carry the heads and my local Yanmar dealer can't get me a rebuilt. I have found a used Head from a YSB as well as a YSE but don't know if they would fit. Not sure what you mean by a "Short Block or Long Block". I assume you mean something other than a YSM which I can get but fitting it into the boat of course can be a lot of work. Rebuilding this motor, if I can get the parts, will probably cost as much as buying another rebuild but avoids the problem of retrofitting the boat for another configuration.
Last edited by superiorvoyager; 12-08-2012 at 11:48 PM.