deisel tractor smoking

[DavidS]

after I run my tractor for about 45 minutes to an hour it starts putting off a blue colored smoke from the exhaust. I am pretty sure it is not oil smoke for 2 reasons, 1. does not smell like oils smoke. 2. I never have to add any oil. Any ideas on what this smoke could be from and how (if any way) to fix it?

 

[TC18guy]

Blue smoke usually indicates a rich fuel condition, unburned fuel blowing through the exhaust. I have no idea what would cause that after that period of time.

 

[normde2001]

All you got on a diesel is fuel, air, (in/out), and compression. You just have to start troubleshooting from easiest to hardest. There's a long list: dirty air cleaner, bad fuel, dirty fuel filter, air in fuel lines, algae in fuel tank, dirty injectors, clogged muffler, valve problems, low compression.

 

[DavidS]

wow!! long list there. guess I will start at the easiest and work to the harder ones. Hope it is something simple!!

 

[Anonymous Poster]

Many in that list result in fuel starvation. It sounds like you may have the opposite problem--too much fuel/not enough air.

I would start with the air cleaner and clogged muffler possibilities. I would also check the oil level in the injection pump, if you haven't already done that, mainly because you mention <font color="blue"> blue </font>smoke. (I'm assuming the engine doesn't have unit injectors, and assuming the injection pump has its own oil supply.)

Keep us posted, and good luck.

SnowRidge

 

[DavidS]

Well the muffler is for sure not it, brand new muffler on it. How do I check the oil level in the injector pump?

 

[Anonymous Poster]

</font><font color="blue" class="small">( Well the muffler is for sure not it, brand new muffler on it. How do I check the oil level in the injector pump? )</font>

I expect that you would have mentioned it if the trouble started when the new muffler was put on--stranger things have happened--but I digress.

Look for a small dipstick. If the pump has its own crankcase, it will have a dipstick to check the oil level. It may screw off or pull out. If it has its own crankcase, it should be pretty obvious. If it does not have its own crankcase, the pump will be lubricated by engine oil and there will be no dipstick.

Although you say the oil is not being consumed, and it doesn't smell like oil smoke, I would still consider oil burning as a possibility. Blue smoke is typically associated with oil burning, not excessive fuel. It's possible you have a combination of both though. If the air intake were restricted, the engine would pull a high vacuum and might suck some oil past the rings.

What I am most curious about is the time lag for the symptom to appear. I've racked what's left of my brain, but can't come up with a good explanation on why the smoke doesn't happen until the engine has been running for awhile, unless you are also having an overheating situation that you aren't aware of. Any chance of that?

SnowRidge

 

[DavidS]

I know blue smoke usualy represents oil burning, that is why this has me puzzled. The tractor has smoked like that since I bought it. And not the problem did not start when I put on the new muffler. I just can't figure out what would make it start smoking after several minutes of opperation!!

 

[Anonymous Poster]

I think a compression test may be in order. Unfortunately, most people don't have the equipment to do that on a diesel.

Tell us a little bit about the tractor. Who makes the engine, number of hours, and so on.

SnowRidge

 

[DavidS]

the tractor is a Bolens G152 which is actually an Iseki. The motor is a Mitsubishi I believe. Not sure of the hours on it, the hour meter was broke when I bought it and stoped at 935 hours. I am figuring it has a lot of hours on it. I am sure the motor coudl probably use a ring job. I bought the tractor because I got it cheap, $1800 for the tractor with a 42" brush hog and a tiller (which needs new tines). The tractor runs good but looks a little rough (just really needs a good cleaning and repainted). I plan to tear it down and rework it one winter when I get a chance.

 

[normde2001]

One other thought, does the tractor have a working tach? Depending on the task at hand, mowing, for instance, if the rpm's drop after a while due to slippage of the throttle, it could be lugging the engine which can cause it to smoke.

 

[ollo_ollo]

Could be worn out rings: knew of a Mercedes Diesel sedan, high milage with 3 drivers. Grandfather, son & grandson. When driven by grandson there was lots of blue smoke & it used oil. When driven by the son, it smoked a little on acceleration but used no oil. When driven by the grandfather (& original owner), it seldom smoked & made oil! Explanation was fuel leakage past the rings when babied, less leakage when driven normally & no leakage when the 18 y.o. tried to hot rod it. Don't know why the tractor only smokes after getting hot but you could be burning a little oil & replacing it with diesel fuel if this is a high hour tractor. Would be a good idea to change your oil often & sounds like a problem that may get worse over time. Don H

 

[bgott]

You could have oil running down the valve guides. It doesn't take much oil to make blue smoke.

 

[looch]

At least in a gasoline engine, blue smoke caused by valve guides will be most evident at startup and should become less as the engine warms up. Still a possibility though.