have yanmar ym2500 (3 cyl eng) 1100 hrs. starts, runs good. smokes upon acceleration.then clears out. smoke is dark grey. just replaced head gasket and valve stem seals. and had inj rebuilt. still smokes. uses no oil so far. possibly trash in inj pump??? what do you think? thx. also, just replaced fuel filter, drained tank and replaced all fuel lines.
fuel smoke
- Thread starter tmar04
- Start date
MJPetersen
Veteran Member
Sounds to me like it is doing EXACTLY like it is supposed to do. smoke under acceleration is absolutely normal. You have done enough work to her, now go do some work with her.
Mike
Mike
RobJ
Elite Member
Yep, sounds good.
No problems pulling the valve springs? There would be some good pics to post there!!
No problems pulling the valve springs? There would be some good pics to post there!!
Yeah, I thought about the pics, but it happened so fast, I didn't have time. simply put piston at top(easy to tell. valves won't depress, other two will) use stud for valve cover as anchor, slip piece of small flat iron down over, replace stud/valve cover nut and pry down. springs depress easily. really is easy with two sets of hands. bro in law pried down with bar, I removed keepers. very easy. only problem, old seals looked great, still got smoke problem, only upon acceleration. I am sure it is excess fuel, becasue it clears up instantly. but oily residue left in exhaust pipe. I mean, really oily!! is that normal?
kevinj
Veteran Member
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tmar04 said:
Does it use any oil? Is it like an oily black soot, oily enough to stick but not liquid or dripping? Perhaps you could fill in your loaction. Sometimes on cold start I get moisture in the muffler and stack during warm up.
dieselgeek
Bronze Member
It could be your injection timing is a bit retarded or late. That will cause more smoke under free-rev or loaded acceleration, than typical. did you check the timing when you went through the engine?
uses minimal amount of oil. about what I would expect from 30 yr old machine. the oily residue is a mixture of oil, soot, and whatever. doesn't bead up like water, just typical diesel black oily mixture. Probably about normal for this age machine. after all, in 1977 tdhe environmental requirements were not so strict. I will just live with it. replacing valve seals did help some. thanks to all.
Kevin, I am in central Georgia. Nice and warm! never have to even use thermo start. fires right up first try, everytime. I know some oily residue is normal, in exh pipe. I suspect most of it is a combination of normal oil usage, and excess fuel. something I can live with. My neighbor has a Kubota, altho it is new, so I will check his to compare. thanks to all.