155 Sluge from exhaust Why?

5030 · Nov 19, 2024

4get gto said:
Kind of agree with winston above. You might want to check into that cylinder in question. Does it clear up after running a bit or does it keep spitting it out. ? Does the cylinder in question get as hot when running ? Should be able to put temperature gun on each individual cylinders to check OR you might be able feel the difference. Be extra careful doing it this old recheck way...normally they don't get as hot as gas motor would..

Depends on how hard you work them more than anything else. Hard working diesels can have exhaust temperatures approaching 1200 degrees (f).

careyo63 · Nov 19, 2024

I repainted the green Yanmar to an International paint code. Motor runs just fine but I am getting black sludge from the exhaust." New injectors and pump looks clean and fine."
That is oil in the exhaust. Broken oil Ring is my guess. Exhaust Manifold shows a problem that Diesel fuel won't cause!

Agvg · Nov 26, 2024

People don't use the tractor hard enough, let it work with high load for a couple of hours, and hard means it pulls with all it has of engine power.

Yanmar155 · Apr 20, 2025

careyo63 said:
Does the muffler have a lid on it to prevent Rain from getting in it or Smell like Diesel fuel. I would be checking your fluid levels and see if your low on anything.
I would get oily carbon bombs on my hood . I pulled the Exhaust and soaked it in gas then blew it all out with the Air compressor. It quit doing it but my lid will get a carbon build up on it that I clean it off every few months and guess that's what it was coming from over the decades. Thin liquid looking?

I store it inside and there is a cap on the exhaust.

Yanmar155 · Apr 20, 2025

Agvg said:
People don't use the tractor hard enough, let it work with high load for a couple of hours, and hard means it pulls with all it has of engine power.

I ran her hard this morning with cardboard in front of the rad and the overheat light came on. Still kicking out sludge but not as much. I also notice that his engine does not seem to make the oil black right away like most diesels I've worked with.

Yanmar155 · Apr 20, 2025

winston1 said:
Noting one cylinder might be causing this you might want to consider loosening injector lines one at a time and see if problem cylinder is different. Carefull with high pressure if doing it. Could possibly be a bad injector. Worth looking into.

new injectors on both cylinders.

careyo63 · Apr 20, 2025

What showing up on the muffler cap lid itself. Antifreeze or white water looking? I get normal black smoke and A thick black sludge on lid cap. Almost thicker than grease. Super nasty black! I use a gas soaked rag which I wipe it off often. Not much of oil use. 1/2 Qt. a yr.. with typical use. 50 Tach Hrs. is normal for it. Cutting grass season 95% of the time. I have had trouble with my Temp sensor. To much anti freese will cause it to trip my light. Stop chk. it and everything is normal and nowhere near being hot. I just had to change it. Started the end of last Yr.. The Org. radiator has always been notorious for getting dirty. 25-35% antifreeze is what I stay around
When It gets hot next time look at the overflow bottle itself. Is the overflow full or you can see bubbles in it? Sure sign of a problem. Keep on it and your eventually find the problem.