Kubota diesel engine

[UncleMerle]

My Skag mower with a 25 hp Kubota diesel engine has given me 13 years of trouble-free operation. On my first attempt to use it this season, the engine "popped" when I started it, and the exhaust began pouring out lots of dense black smoke. The exhaust sputters and makes a sizzling sound. The soot it left behind is dry and powdery and the crankcase oil level registers "full". The engine does not respond to the throttle. It struggles to run at low rpm's and stalls out in about 30 seconds. I can restart it, but with the same results. Oddly, if I try to shut it off with the ignition key, it continues to run for several seconds before dying out. What could be causing this situation and how extensive are the repairs likely to be? Would I be better off to pay for the repairs, or trade in a 13-year-old non-working mower for a new one?

 

[ptsg]

Start by taking the air filter off and see what's the condition of it, since this is often overlooked. Sometimes creatures with make a nest inside the air cleaner and can create the symptoms you're experiencing.

 

[5030]

Eliminate the obvious stuff first. Sounds like a plugged air filter to me.

 

[UncleMerle]

I had previously checked the air filter, but in response to these suggestions, I ran it both with and without the air filter in place - no difference between the two. But now, instead of stalling out in a few seconds, it continues to run but sounds like it will stall. Still black smoke and no response to the throttle.

 

[5030]

Sounds like pump or injector issues but could be a blocked fuel filter or bowl filter too.

I take it you are lax as far as maintenance is concerned.

You might want to PM PumpServiceGuy on here. he's the pump expert.

I'd be eliminating everything from the fuel tank (blocked fuel cap) to the pump first and that includes all filters as well as the brass screen filter in the pre pump bowl.

 

[UncleMerle]

Thanks. Not lax - have the machine serviced annually. Correction about not stalling - it still stalls.

 

[Fxfymn413]

Black smoke indicates over fueling and its lack of power indicates too little fuel when needed. I'd check the injection pump to see if a bolt came loose and caused it to go out of time. I am not familiar with what drives the injection pump, but if it is a chain or belt I'd give that a close look as well.

 

[dodge man]

I’d replace the fuel filter or filters if there is more than one. Then see what happens.