ym186 billows white smoke and no power

[pegs11]

I have a YM4186D 3 cyl diesel that just started blowing smoke and lost most of the power. I was just driving it across the yard when it started. So far.

I have checked and cleaned the air filter. drained and replaced the diesel fuel, check the flow through the fuel filter.

I tried bleeding from the fuel lines at the fuel pump but only got a small amount of fluid... not sure what to expect there.

Also tried bleeding them at the injector and go the same results.

Also when starting it the back cylinder... the one closest to the steering wheel doesn't get hot right away.....while the front does.

I loosened the injector bracket and got a spray for there so the injector must be getting fluid.

Changed the oil..... no water in the oil.

Radiator fluid looks bad, so I'm going to flush that and see if its just old fluid.

 

[shakin]

white smoke is bad. do a compression check diesel engine-white smoke= head problem.

 

[Willl]

white smoke is bad.

No it isn't, white smoke on a diesel means unburnt fuel.

 

[Willl]

I have checked and cleaned the air filter.

Replace it.

 

[Egon]

As mentioned, do a compression check.

 

[roadhawk]

Just a guess but check the head gasket. It could be failing and letting in coolant. If it gets bad enough you could have some serious engine problems since "water" doesn't compress.

 

[California]

If you suspect the head gasket, remove the radiator cap and watch a cold start. Combustion pressure in the coolant can show as a visible surge coming in from the upper hose.

Also if you suspect the headgasket, be sure to precede every start by cranking using the compression release, to blow out any water from the cylinders. Water is incompressible and will break rings, or worse.

 

[pegs11]

I'll check all of this over the weekend. Thanks for all of the replies.

I really do want to save the little monster.

 

[shakin]

black smoke is unburnt fuel.

 

[rScotty]

I have a YM4186D 3 cyl diesel that just started blowing smoke and lost most of the power. I was just driving it across the yard when it started.

It doesn't sound so bad to me. I've got my suspicions as to what it is, but first I'd like for you to reach back in your memory....or simply go out to the tractor if it is running....and grab a couple of more pieces of information.
What had you been doing right before it started blowing the white smoke? Can you sort of walk me through the sequence? Was it on a slope?

Tell me a little bit more about #3 cylinder not getting warm as fast as the fronts. Usually the rear cylinders are the hot ones. How do you know? What does it do?

Reading through the answers, there seems to be some disagreement about what the color of the smoke means. I've been a mechanic all my life. Unburned fuel can be either white or black. When one cylinder isn't igniting at all, the exhaust from that cylinder will be a white fog - which is carried out along with the normal exhaust from the other cylinders. At very low RPM every third exhaust pulse - or every time that cylinder misses - the exhaust seems to turn white. The exhaust header from the cylinder that is not burning well tends to be colder than the other.

If on the other hand the motor is "overfueling" - which means that the injector is putting out too much fuel for the amount of air that it is sucking then what comes out of the stack is dense & black. Black smoke can either come out evenly from all cylinders if the overfueling is being caused by the governor...or in pulses like above if the overfueling is caused by a bum injector. Overfueling will often cause overheating.

So both white or black smoke from the exhaust can mean unburned fuel. Another thing you want to know is whether the exhaust smoke is fuel fog or coolant steam. That test is in the smell of the exhaust smoke. If it is unburned fuel fog then the exhaust smoke will have a pungent diesel reek - much stronger than usual. You won't miss that. If the problem is a coolant leak into the cylinder head, then the exhaust smoke is the steam from a water+antifreeze mixture. That one has a sort of sweet smell but isn't nearly as strong an odor as the fuel fog.

Which one do you suspect it is?
Good Luck......rScotty