Yanmar YSM12

Figment · Post by **Figment** » Tue Oct 12, 2004 12:17 pm

I had the pickup and was in the neighborhood yesterday, so I stopped at John the BeerGuy's house and picked up his old diesel. It's not a GM10, it's a YSM12.

Horizontal. W I D E. Yikes.

Anyone have any experience with this engine?

Post by **Tim** » Tue Oct 12, 2004 1:55 pm

I've seen a few of those, and even more of the smaller YSM-8, which is basically the same engine (with fewer horsepower). They were the "next generation" from the YSB series, like the miserable YSB-12 that I first had in Glissando. I'm not sure exactly what the changes from the SB to the SM series were, but the engines are very similar in concept, looks, and overall ability.

My own YSB-12 experiences aside, there are hundreds of those old Yanmars out and about that serve their owners well. The older they get, the crankier, though. They are not very refined engines, but they get the job done in most cases.

The width of the horizontal block is a real problem for a Triton; off the cuff, I doubt it would fit in the original engine room. They're pretty "chuffy"--you can feel each pulse of that single cylinder, back and forth. They like to be run pretty hard, and need to be, in order to create any power at the prop.

If the engine runs well and reliably, and you can make it fit in a manner that doesn't rob you of too much valuable room elsewhere, then you might be happy with it. Just don't be expecting refinement, smoothness, and quiet!

Figment · Post by **Figment** » Tue Oct 12, 2004 2:12 pm

Space shouldn't be so tough to accommodate. It's asymmetrical, wider to starboard than to port. It should just take a bite out of that impractical-to-use-anyway storage compartment in the aft portion of the galley module.

The rough running, on the other hand, may drive me nuts. I don't know that I've ever been on a boat with one of these running, and I may need to find one and beg for a ride before I go through with this. The DONK-DONK-DONK-DONK of the 1GM powered boats I've known has never really bothered me, but this thing may be a horse of a different color.

Is is just me, or is it really counterintuitive to have the impact force (for lack of a better term at the moment) of an engine run horizontal when the mounts are vertical? It seems to me that these things would be prone to vibrating themselves out of alignment.

Post by **Tim** » Tue Oct 12, 2004 3:33 pm

They definitely vibrate! Of course, some of the vibration and movement typically seen is the result of solid mounts, or tired, neglected damping mounts. I haven't seen one of these in a new installation situation. I'm sure it would be better in that case.

Just be sure you know what you have first, and avoid disappointment later. That was my mistake, one that never shall be repeated.

Figment · Post by **Figment** » Wed Oct 13, 2004 11:21 am

I hear ya. I think I'm going to bring this thing to Mack Boring, describe the history/problem, and tell them to call me when they've got it squared away.

Yeah, they're not exactly around-the-corner, but the local Yanmar guy is (forgive me) an absolute shithead whose answer to everything is "she's air-bound". When bleeding doesn't work he calls in Mack Boring, then adds a 15% admin fee to MB's road mechanic's bill. I might as well cut out the middleman on this one. I have a run to Philadelphia coming up soon anyway, I think.

Figment · Post by **Figment** » Tue Nov 09, 2004 8:34 pm

After a long hard think, I've come to grips with the resolution that this horizontal engine simply is not a good fit for the Triton. Could it be made to work? Yes. Is it a worthwhile effort? Not likely.

Still, Mack Boring is going to fix the runaway problem (they've said it's something simple little thing that they see all the time FWTW) so if you know anyone who needs an engine......