Komatsu sk1020 non turbo

[James204]

Hello everyone, I purchased a sk1020 a few days ago . I got it pretty cheap because it needs some repair. The main problem I can't figure out is at full throttle it smokes blue starts breaking up and then smokes black. It does it worse under load while driving. I checked air filter so far. Thanks for any help. I have a video that I can email.

 

[flyerdan]

As a rule, blue smoke indicates that it's burning oil, and black smoke indicates unburned fuel.
It would probably be a good idea to have a compression test done to see if one or more cylinders are weak, and have the injectors bench tested. That will give a starting point on where to begin.
It sounds like you might have a weak cylinder, which would account for the oil bypass, and when it's worked heavily it won't fire, resulting in the excess fuel in the exhaust, and rough running. Just a guess.

 

[James204]

As a rule, blue smoke indicates that it's burning oil, and black smoke indicates unburned fuel.
It would probably be a good idea to have a compression test done to see if one or more cylinders are weak, and have the injectors bench tested. That will give a starting point on where to begin.
It sounds like you might have a weak cylinder, which would account for the oil bypass, and when it's worked heavily it won't fire, resulting in the excess fuel in the exhaust, and rough running. Just a guess.

Changed fuel and air filter with no change. Cracked each injector and they all cause the engine to shake. I've also found anytime I open my radiator cap there is pressure in it. The smoke is actually blue not black.

 

[James204]

Changed fuel and air filter with no change. Cracked each injector and they all cause the engine to shake. I've also found anytime I open my radiator cap there is pressure in it. The smoke is actually blue not black.

I'm going to get a pressure tester. I'm pretty sure its leaking combustion into the radiator. I found they only have water in the cooling system. Anytime the engine turns there is pressure buildup in radiator. There is no water in the oil .

 

[Tazza]

I'm going to get a pressure tester. I'm pretty sure its leaking combustion into the radiator. I found they only have water in the cooling system. Anytime the engine turns there is pressure buildup in radiator. There is no water in the oil .

So, you mean the radiator is building up pressure when it has not been running long? as when it runs, it gets hot and builds up pressure as it expands.
If you are saying there are bubbles and pressure build up as soon as it starts, you have a cracked head or blown head gasket. It would explain the smoke, as oil can get into the cylinders through the crack or bad gasket.