YSM8 big issues!

[karonoko]

Motoring out into Casco Bay today in my CD 27 with original Yanmar one-lunger (1981) and BOOM! Big noise, huge black and gray smoke, engine throttle ran up out of control. Did i blow my engine? Sailed back to my mooring through my cloud of carbon with a sinking feeling and a pain in my wallet.
There may be a fix, I am told by my mechanic, but then I will have this little voice that will keep saying, when I need the engine most, “your engine is going to blow, right now and you will be screwed.” Peace of mind?
Should I fix or repower?
Repower could cost much more than the boat’s value….but then again, who would buy a boat with an engine that might be on last legs though “fixed.” I a, not going to sell and want another 10-15 years with her if possible.

Any thoughts out there? Thanks. Tom Duffus, CD27 #216 Scotia.

[Walter Hobbs]

Have the same boat and same engine. 77 vintage. Engine has been very reliable. Following, curious to see what is wrong with your engine.

[karonoko]

Will report back!

[jfischgrund]

Just went through the same thing with my 27'. It's called "runaway diesel" and it is indeed scary. First I thought it was the injector valve, replaced it, and that did not fix it. It just got worse -- checked the oil and it was gray. A sure sign of water in it.
Your reasoning about the value was similar to mine. I've done lots of research on the whole thing and decided re-powering is the way to go. I would be happy to discuss it if you want to PM me.

[jfischgrund]

Just went through the same thing with my 27'. It's called "runaway diesel" and it is indeed scary. First I thought it was the injector valve, replaced it, and that did not fix it. It just got worse -- checked the oil and it was gray. A sure sign of water in it.
Your reasoning about the value was similar to mine. I've done lots of research on the whole thing and decided re-powering is the way to go. I would be happy to discuss it if you want to PM me.

[karonoko]

What did you repower with?

[mgphl52]

Your problem could be a stuck governor. I had this issue with Allied Princess I previously owned. She had been on the hard for over 3 years and when we were servicing her before relaunching. The Yanmar 3GM30 did the same thing (but without the BANG). I put vise-grips on the fuel line to shut her down. My buddy was able fiddle around with the governor and get the issue resolved.
However, having a milky look to the oil is never a good sign. It could be simply a blown head gasket and with little compression the engine raced. I would not right it off completely until after pulling the head and checking the gasket, valves and compression release, all of which can probably be done without pulling the engine.

[jfischgrund]

I am re-powering with the 1GM10. I decided not to go to the considerable expense of having the motor removed and the head pulled off to even see if it could be rebuilt, only to find out that I would find out that it really could not be saved or that a rebuild would be tenuous given the age of the engine (40+ years). The 1 GM10 is the closest thing to the YSM8 and will present the fewest problems installing it. Some people go with the 2GM14 but the installation is more difficult due to the size of the engine. I believe it weighs significantly more and I was concerned that it would change the sailing characteristics of the boat. The 1GM10 is an EPA non-compliant engine, but so is the YSM8, so you are allowed to replace one non-compliant engine with another if you fill out a form stating that the old one will not be used, so that in effect, you are not adding another non-compliant engine to the environment. Incidentally, the 1GM10 is not always easy to find -- I'm not sure they still make them. Mack Boring is the distributer I worked with.

[Ken Textor]

Having once repowered a CD 27 with a Yanmar 1GM 10, I can say I wholeheartedly agree with jfischgrund. The YSM8 was originally designed to be power for an irrigation pump, the marine application was secondary. When I replaced mine, it wasn't even in as bad a shape as the one described here. It was just time. I did the replacement myself, which was a mid-level DIY project. I just had the boat hauled to the side yard and went at it. And when that new engine fired up, and fired up reliably for the next six years, and was MUCH quieter than the old YSM8, I thought it money well spent. Peace of mind is priceless. PM me if you want to know more. I live about 20 minutes away from Casco Bay. Good luck,

[karonoko]

Thanks for the encouragement. Anyone out there have Success with the Beta engine? I have read about issues with the 1GM10….water in oil. And, looking for a source for whichever I chose that wont charge me the overhead of a marina.

[Ann and David Brownlee]

Same thing happened to us on our 27 about 25 years ago. First, we had the runaway problem, when motorsailing and heeled down in the mouth of the Patuxent. We think that had to do with the fact that, when heeled, crankcase oil can be burned: lots of smoke, not throttle control.

A couple of years later we had a version of the "big bang." We had the engine diagnosed and rebuilt, expertly, at Yankee Point Marina on the Corrotoman. Basically, a new cylinder. Ran fine after that! In 2000 we sold the boat and bought our 31. Rebuilt its engine in 2012.

[fmueller]

I repowered with a Beta 14. Fits no problem.

When I first bought Jerezana the mechanic that looked at the original YSM motor for me said “ There’s good news, and bad news; this motor might run forevah - but also, this motor might run forevah.”

I bought the boat in Belfast ME. He was referring to the pretty healthy noise those old motor make.

[karonoko]

Fred what did you do about the brackets for the engine mounts?