kubota blue smoke, loss of power

[jomama]

kubota starts fine but after warm up loses power and blows blue smoke. only thing so far is that fuel filter has been changed and air filter etc cleaned and checked.

 

[85Hokie]

By chance - have you checked your engine oil? IF so - was it high on the stick?

What type/ weight of oil are you using? Reason for asking, as hot heats up - it thins and this could allow oil to get by the rings.

 

[TheOldHokie]

What type/ weight of oil are you using? Reason for asking, as hot heats up - it thins and this could allow oil to get by the rings.

In that case I would opine the rings are worn out and likely a major contributor to the loss of power and smoking.

Dan

 

[jomama]

kubota starts fine but after warm up loses power and blows blue smoke. only thing so far is that fuel filter has been changed and air filter etc cleaned and checked.

15/40

 

[Trash Panda]

How many hours are on the unit?

 

[Ryansfarm]

Blue smoke is usually considered to be the engine burning oil, however, my Kubota also spews blue exhaust and it is unburnt fuel. The fuel is so raw it burns your eyes and has a different smell than normal diesel exhaust. I would start with the injectors or injection pump, possibly pump timing. However, my local Kubota dealers have been unable to resolve my tractors loss of power.

 

[jomama]

How many hours are on the unit?

1182 hours

 

[jomama]

I was inclined to think it was the blower as my allis charmers did the same thing a number of years back. Fuel filter was dirtier than ever seen which was kinda strange but good fuel pressure to filter and pump

 

[lugbolt]

what is the compression pressure?

 

[Trash Panda]

Blue smoke is usually considered to be the engine burning oil, however, my Kubota also spews blue exhaust and it is unburnt fuel. The fuel is so raw it burns your eyes and has a different smell than normal diesel exhaust. I would start with the injectors or injection pump, possibly pump timing. However, my local Kubota dealers have been unable to resolve my tractors loss of power.

I agree here, I’d start diagnosing high-pressure fuel system issues.

 

[whitetiger]

I’d start diagnosing high-pressure fuel system issues.

Yes, let's jump right past the simple common checks/tests and start spending big money.

 

[Trash Panda]

Yes, let's jump right past the simple common checks/tests and start spending big money.

I don’t think that the cost of a fix negates the probability of it being the issue, and diagnosis at home costs nothing.

 

[pigdoc]

Ya, when ring clearance gets destroyed, a diesel engine basically uses crankcase oil as fuel. I've run a burned piston in a Cummins for about 50 hours, and it was burning a quart of crankcase oil every 10 hours. Not a harbinger of imminent catastrophic failure, just a sadly inefficient engine, both in terms of power and "fuel" efficiency.

If your crankcase oil level is increasing to cause the smoke, it could be due to leaking injector pump seals. Not sure about Kubota engines, but fuel bypassing weak injector pump seals can end up in the crankcase, too. [I have never understood why the fuel that is bypassing the injector pump seals could not be directed somewhere (anywhere) OTHER than the crankcase, by design...] Excessive fuel pressure upstream of the injector pump can cause the same problem, with the end result often being catastrophic seal failure in the injector pump. Been there, done that. Twice. I've seen engines puking fuel out of the crankcase vent when running (enough to see the stripe on the road in your rear view mirror). Last time that happened to me, I was in the Balto Inner Harbor Tunnel, towing a load. Not Good. White Knuckles. Looking for the next off-ramp...$400 tow bill imminent.

Bottom Line: You do NOT want to be using diesel fuel as a a lubricant in the crankcase!
-Paul

 

[Captain13]

I was inclined to think it was the blower as my allis charmers did the same thing a number of years back. Fuel filter was dirtier than ever seen which was kinda strange but good fuel pressure to filter and pump

Have you checked looked Inside the turbo to see if you have oil there? If the turbo seal is leaking, it will give you lots of blue smoke. The seal could be failing and that’s why you lose power as it warms up.