Black smoke after overhaul

This one has me scratching my head. I just overhauled this engine. Interstate McBee parts. It's a Yanmar 4TNV. Overhaul done because they ran it without an air filter. More accurately the air filter cover came off, filter wiggled out and bob's your uncle. Overhaul done, and it's smoking like crazy. It did not smoke like this when it came in, by the way. Had some white smoke because the compressions were low, but no black smoke. I have experimented with fuel injection timing. In a Yanmar you have slots in a gear in the timing case. I've moved the timing all throughout those slots, no change. The injectors are original and test perfectly on a bench, cracking within about 150 psi of each other, right on spec. I can't remember what that is at the moment, maybe 2500 psi or so, maybe 2300. Something like that. New turbo, gives about 9-10 psi boost at full nut. Static compressions all between 300 and 310. This is Denver, so the slightly low boost and low psi numbers are normal for this area. Black smoke happens with or without muffler, with or without air filters. Everything looks normal, but the smoke persists. If I was a tooth off on valve timing, it wouldn't run this smoothly, right? So it can't be that? Anyway improper valve timing tends to make white smoke not black right? Black smoke means too much fuel, not enough air, or incomplete burn. What, in this situation, would cause incomplete burn but valve timing? If my valve timing was off, I would also not get 300 psi static. I'm talking in circles because my brain is circling the drain. It starts and runs perfectly. Just smoking like my old Aunt Dottie and her Pall Malls. Any ideas, I'm all ears. Thanks for reading!

Had to check, it was driving me nuts wondering. Timing marks are spot on. View attachment IMG_3785.jpeg I tried rotating the engine until they lined up again, but that could take ages, so I just reset timing. Anyway. Timing is ok. I checked fuel pump too. The picture in the manual suggests if you lined up the pump like this: With the "void" in the pump shaft pointed downward, that's firing position. But the engine won't run like that. It needs to be in this position: And it runs just fine. Except for the smoke. In any case, it's not compression, valve timing, filters, exhaust, or turbo that's causing it. I've eliminated those. I don't see how it could be fuel timing related because those 4 bolts in the pump gear pics have short slots under them, and I've run it throughout those slots with no change. I'm thinking it has to be related to fueling. The injectors aren't new, but check just fine on the bench. The pump has no fueling related. external adjustments on it either, so no way I could have boogered that up. I think.

How did you confirm the turbo is good? Especially, after a dusted engine. Sheridan is 5,000 ft. That little engine needs all the manifold pressure it can get. Did you check the boost pressure ?

Coaldust said: How did you confirm the turbo is good? Especially, after a dusted engine. Sheridan is 5,000 ft. That little engine needs all the manifold pressure it can get. Did you check the boost pressure ? Click to expand... Boost is 9-10. Oddly though, when I ran the engine initially with the dead turbo, it got no boost, even generated a little vacuum at full throttle. With the new turbo, it's 9-10 full throttle and the smoke is exactly the same.

How long has it been run since you fixed it? Do you think the muffler might be wet from the lube oil it collected before it failed?

Coaldust said: How long has it been run since you fixed it? Do you think the muffler might be wet from the lube oil it collected before it failed? Click to expand... A week. I thought about the muffler. Maybe it got all oil fouled from the original turbo going TU. I took it off today and ran it. Same smoke, and it's black and smells like fuel, not blue smelling like oil.

is the pump keyed to shaft I had one black smoke as soon as you put it under light load timing was off

Dave Neubert said: is the pump keyed to shaft I had one black smoke as soon as you put it under light load timing was off Click to expand... There is an adjustment that gives you maybe 20 degrees of CS rotation in the adjustment range. That's the 4 bolts I mentioned earlier. I moved throughout that range and on the retard end, it won't even start, but I tried 8-10 positions within the remainder of the adjustment range and no change in the smoke.

And piston numbers matched?

Truck Shop said: And piston numbers matched? Click to expand... Yes

I'm sure you already checked simple stuff. Years ago I was working on a machine and put a rag in the intake tube to keep anything from getting into it while I had the air cleaner off. Later on I finished up the project and started the machine and it idled fine but didn't have any power and smoked badly. I had forgotten to take the rag out and it had gotten sucked into the intake manifold blocking air flow.

materthegreater said: I'm sure you already checked simple stuff. Years ago I was working on a machine and put a rag in the intake tube to keep anything from getting into it while I had the air cleaner off. Later on I finished up the project and started the machine and it idled fine but didn't have any power and smoked badly. I had forgotten to take the rag out and it had gotten sucked into the intake manifold blocking air flow. Click to expand... Hah! Point. I actually don't use cloth rags. But no, no rags of any kind stick in any places. At one point, I took the intake tube off the turbo inlet to see if that changed the boost. It didn't, but it didn't change the smoke either.

Don't ya hate it when your brain kicks into overdrive right as you're trying to sleep? It's almost 4:00 am, and I've been up all night thinking I installed the nozzles wrong. Or more accurately the seat gaskets. These things have a nozzle protector, and a seat gasket at the nozzle. The seat gasket being the common copper washer. The nozzle protector is just a short steel sleeve you install on the nozzle. What I'm thinking is, I have a nozzle protector, seat gasket and another seat gasket at each injector. 2 coppers. That could cause black smoke. If those tips aren't right where they should be, and the spray pattern is moved a little out of the cup in the piston that could create an incomplete burn situation. This is what I've been telling myself all night. I would have got up and gone over in the middle of the night but my wife and daughter would have killed me for waking them up on a Sunday night. They expect that crap from me during the week, but not on Sunday. Ugh. I have an other hour before I can safely get up without the fear of the estrogen fueled retribution.

Eureka. That was it. I've been doing this long enough to at least listen to those little voices that wake me up, but apparently not long enough to prevent rookie mistakes. In this pic, the upper injector is how it's supposed to be. The middle injector is how they were in the engine. My confusion had to do with the nozzle protector. It's plastic, not steel and crushes into place upon installation. That's why they tell you to replace em each time. They were part of my kit, but I incorrectly assumed they were for a different model. The lowest injector shows the removed protector and the seat washer kind of stuck together. I thought that was one part, and that was the protector. I didn't know the sleeve was plastic and came apart from the washer. Anyway problem solved! Here's a little vid showing NO SMOKE! Thanks for the tips y'all. Even though nobody hit the nail on the head (myself included), just talking about it helped me think it through. I appreciate you!

Sometimes the solution is discovered laying in bed. Glad that worked out!

glad you figured it out

materthegreater said: I'm sure you already checked simple stuff. Years ago I was working on a machine and put a rag in the intake tube to keep anything from getting into it while I had the air cleaner off. Later on I finished up the project and started the machine and it idled fine but didn't have any power and smoked badly. I had forgotten to take the rag out and it had gotten sucked into the intake manifold blocking air flow. Click to expand... Been there done that. Rebuilt an 855 Cummins. Ran ok at idle but was running rough higher RPMS. I floored it and after some grumbling, a shop rag on fire came flying out of the exhaust. Ran fine after that.

oarwhat said: I floored it and after some grumbling, a shop rag on fire came flying out of the exhaust. Ran fine after that. Click to expand... Clint Eastwood said--A mans got to count his shop rags when done.