Black smoke

[steviep]

So I just got my 4300 back together again. This time I had the injectors checked and rebuilt. Now it's blowing what I won't call black but very dirty smoke. I have been told that air in the lines will cause this. What's everyone's thoughts.

 

[Kubota 2350]

Sounds like the injection timing needs to be checked and adjusted.

 

[mike48130]

How much? Assume it is worse than before? Air in then lines will be gone in short order at high rpm with those short lines.

How many hrs and what work did you do to it? And why?

 

[steviep]

Last year the engine was rebuilt , this year I blew the head gasket. The head did over heat but it didn't get warped , put a new head gasket in and reassembled. While waiting for the head to return the injectors were sent out tested and rebuilt. Engine starts right up just really Smokey.

 

[cruz54982]

black smoke is usually caused by lack of air or to much fuel = mouse nest in air intake while engine was apart ? or any other obstruction in air .

 

[steviep]

No blockage, I had it all off including the manifold and cleaned it all before putting it back together.
It seems to be like really dirty exhaust not so much like black soot. If the injector timing is off I know the pump only has about 3/8 adjustment and I know how to loosen it to adjust the pump . But do you adjust it by eye in till the smoke clears up.

 

[mike48130]

If you didn't adjust it I wouldn't until you absolutely have to. There is a timing procedure in the service manual.

I would remove the nut on one injector line at a time, then start it and see if it gets better. Maybe you can identify one cylinder causing the problem.

I would call the shop that did the injectors as well. Did they set the springs correct? I think the manual has the settings for the springs and shims.

 

[larboc]

No blockage, I had it all off including the manifold and cleaned it all before putting it back together.
It seems to be like really dirty exhaust not so much like black soot. If the injector timing is off I know the pump only has about 3/8 adjustment and I know how to loosen it to adjust the pump . But do you adjust it by eye in till the smoke clears up.

Spillover timing is adjusted by making a tube tool out of a wd40 straw and an extra injector line. The right side loader arm has to come off to see the mark, and it's not a very accurate way to do it IMHO because there is no pointer, just trying to center it up in a cast iron hole. Keep in mind the rear most cylinder is cylinder #1 in yanmar world. You should at least check it to see where you are. I'm suspicious of your timing set marks. There is enough adjustment in the IP timing to blow a head gasket, BTDT.

With it idling, you can crack each line at the IP to kill each cylinder and see if it makes a difference. I'd guess one of the injectors didn't get put together correctly and is dribbling. Cracking the nuts will tell you right away if it's a certain injector.

FYI you can get the injectors out pretty easily. Pull the air cleaner and hose, reservoir tank, injector line clamps, injector line nut at the IP of the cylinder you're going to pull, and put a spray paint can cap over the intake to keep extra parts out of the engine. You can fish your way into the injectors and pull them out, even #1, without pulling the tank. Lightly sand the copper washers and reuse them, they will be fine. Make sure your return line is in good shape and clamped onto the injectors.

 

[jd110]

Extra smoke can also be caused by low compression. Usually smoke from low compression is light gray or white due to incomplete combustion. Loosen one injector at a time and see if smoke clears when one cylinder is loosened. Then pull nozzles and check compression. If compression is good on all cylinders, then send nozzles in for recheck.

 

[DLTTrekkers]

Returnline pinched or blocked ?