Kubota surging

[Timdoll]

Kubota Tractor moving along like normal and my M9000 just started running away with itself, does anyone have any idea whats happening? i have began to take steps to remove head and injector pump need to know about pinning motor or just pull pump?

 

[Jerry/MT]

Kubota Tractor moving along like normal and my M9000 just started running away with itself, does anyone have any idea whats happening? i have began to take steps to remove head and injector pump need to know about pinning motor or just pull pump?

Before you start taking the machine apart, do some diagnostics! Check the control linkage, the fuel delivery, etc. It's usually something simple.

 

[Phillip w]

I have to agree, look for the simple stuff first.

 

[MHarryE]

Also detail on what you mean by running away with itself. Enging revving with no control? Can't turn engine off? Up and down surging but engine never over?
speeding

 

[Dave M7040]

Many Kubota's operating in cold weather have had serious run-a-way problems with crankcase vent systems freezing up.

In some cases, the increased crankcase pressure has forced crankcase oil up the turbo drain line and then the engine is running on crankcase oil and you have lost control of it.
Certain models are affected and I do not have a list. Kubota USA would know. Better dealers would know. Even their newest large tractors are affected.

The fix usually involves heating devices, insulation and sometimes a larger alternator to be able to power the heating devices.

Other Kubota's have had moisture problems affecting the movement of the injection pump rack.

Starting to tear things apart thinking you will find an obvious problem is most unlikely.

Dave M7040

 

[thepumpguysc]

IF it was freezing out while you were running.. gelling fuel would be my guess.. DONT rip it apart just yet.
& no, you don't need to pin the engine before pulling the pump..
The pump sits on its own camshaft that remains in the engine after the pump is removed.. timing is done w/ shims underneath the mounting flange of the pump.. the shims raise & lower the pump off the camshaft to effectively change the point of injection.
Only a couple of things would have caused the "run away"..
Freezing temps got ahold of the fuel, either gelling it or freezing any water that was in the system, locking the control rack in the inj. pump..
A SERIOUS problem w/ the governor system but that normally slows down an engine..
An engine running on its own oil, being pumped to the top of the pistons.. turbo or bad rings..
An injector that blew the tip off.. flooding the top of the piston.. LOTS of black smoke..
A broken gov. control spring that links the gov to the pump. I've seen THAT ONE more than all the others.
Let us know whatcha find.