Yanmar YSM 12 - Troubleshooting Help

[wheatfieldcrows]

Well I may have tried to edit my update post too many times as it got sent to the mods for approval but long story short injector is stuck with a capital S in the head. Building an extractor for tomorrow.

[Aswayze]

I went through this with my YSE-8.

2 things, firstly the return line is M8-1.25 threaded so if you have clearance it is pretty easy to make up a slide hammer and withdraw it that way.

If, like me, you are blessed with a small engine bay and angles that preclude the use of a slide hammer you can make up a little puller like I did to get mine out:

[Wotname]

Nice work Aswayze

[Aswayze]

Anything to avoid taking the engine out.

Which I then did anyhow... cause I am that way...


If it is not immediately apparent how it works:

That's just a bar threaded on each side with a long bolts that are adjusted to position the "puller" part over the injector. The puller portion is a larger cap screw, in this case a 5/8-11, drilled through to allow an M8 screw to pass through it. The M8 screw goes into the injector return line hole then we use a 13mm wrench to hold that one still while we back the bigger bolt out slowly pulling the injector out. I had limited clearances so my bolt had to be short and therefor I had to reset and do it twice to get it out but it did come right out.

[wheatfieldcrows]

Well I built a crappy version of an injector puller with parts I had around and it just bent the plate pretty easily. I then built a hardier version with steel HSS and grade 8 bolts and managed to run out of human power to turn the wrench. This doesn't happen very often to a guy my size. Threw on a cheater bar and got a little more out of her but started to round off the nuts and the injector hadn't moved at all!

Threw in the towel and took the cylinder head off to see what was going on inside. Broke the rusted coupling from the mixer elbow to the exhaust manifold. Is it still a manifold if there is only one cylinder, haha. Pictures of the adventure should be attached. Comments on head and cylinder condition appreciated.

I might just take it in to a shop so I can work on some other projects I need to get done but we'll see... it has been a long few days. I felt like I was locked in eternal battle in fuel injector Valhalla... at some point I kissed a wrench for good luck.

[wheatfieldcrows]

Anyone have a favorite marine diesel shop in Kemah, Tx?

[Aswayze]

Surprise! The part that broke on the exhaust is left hand threaded. Ask me how I found out...

At this point, you have good access for giving it a good slide hammering.

[Compass790]

Looks to me like you have the classic case of Yammer elbow disease where the cooling elbow fails and leaks water down on top of the exhaust v/v. See how yr piston is eroded on one side, the water ingress does that. Good chance compression wont be too good & rings are stuck at least some. If you have access to a heating torch try heating the injector then letting it completely cool then try yr puller again. If you can weld I'd advise making up your own exhaust elbow out of Schedule 10 316L ss. Can send you a pic of a homemade exhaust if you want. You will need to give it a valve grind too.

[Wotname]

Before getting to brutal with the injector, I would immerse the head (sans valves etc) in diesel for a few days and then have another go at getting it out.

In my case, I couldn't (or didn't know how to) get the pre combustion chamber out after removing the injector. The head shop got it out - presumably without too much effort.

Looking forward to hearing of your success!!!

[Compass790]

Wotnames' & Aswazeys' suggestions are better to try 1st. Being a boilermaker type ( ironworker in American) my fallback is heating & beating. Injector nozzle has extremely fine tolerances & better not to risk warping.
Good luck

[Compass790]

Had another couple thoughts, if you can get the injector nozzle outa the holder ( the bit thats stuck ) it will be a lot safer to get a bit medieval on it. You can try heating it too with the puller loaded. But again safer to try soak & slide hammer 1st.

[wheatfieldcrows]

Well, gave it my all including a slide hammer and blow torch. Finally dropped it off at the machine shop. They got it out but I think they destroyed the pre combustion chamber in the process. Got a new injector already as the old one isn’t round anymore after the level of abuse. Chapter 2 starts tomorrow.

[Wotname]

Originally Posted by wheatfieldcrows

Well, gave it my all including a slide hammer and blow torch. Finally dropped it off at the machine shop. They got it out but I think they destroyed the pre combustion chamber in the process. Got a new injector already as the old one isn’t round anymore after the level of abuse. Chapter 2 starts tomorrow.

Good and bad news I suppose.

I hope you track down another pre com chamber. Out of interest, can you post a picture or two of the damage to the pre com chamber?

Roll on chapter 2 .

[Compass790]

Man you doing it tough! surprised you couldn't get it out. Looking fwd to Chap 2 also & better luck.

[wheatfieldcrows]

After close inspection it would appear all the bits of metal were not just from the precombustion chamber but also from the head itself. It would seem the well that the injector and chamber fit into must have had a crack. This would have allowed communication between the cooling water and the outside of the injector/chamber causing them to rust together. When they finally got the injector to break free it also caused the wall of the head that separates the cooling water from the injector to break. I've marked the area with a red X in one of the diagrams I've attached.

Looking closely at the diagrams of the PC Chamber it would seem there is some sort of pins in it. I wonder if they might have tried pushing the precombustion chamber up and the pin sheared off the wall?

The upper (rear) precombustion chamber is largely intact but looks like it might have part of the injector attached to it! The lower (front) precombustion chamber is in pieces.

It is about $1000 in new parts here in the US to fix the head (including $590 for a new head) and then I can finally find out if the piston rings are any good.

Doing some digging to see if I can find a used head (Wotnam caught asking here already) but there is some schedule pressure to consider!

To add insult to injury one of the ears of the exhaust manifold snapped off under slight finger pressure. Thinking about just welding that back on for now.