Engine quits with no warning sounds

[Derf]

On my L4630 GST, I have been using a friend's chipper/shredder on the PTO, and it works fine for about a half hour, then the tractor shuts off with no indications it's about to quit--no bogging down, no shuddering, it just stops. I can restart it immediately but it shuts down quicker after that. I don't see any idiot lights when I restart, but I'm not in the cab when it shuts off.

I bought the tractor used 4 years ago, and this is the first implement I've tried using the PTO. It never quits while I'm driving or in the seat, but I can't feed the chipper, obviously.

I've read some threads about stall protection shut-offs and seat/occupant switches, but those don't seem to apply, unless there's something that gets warm over time.

Anything else I could check?

 

[#40Fan]

Is there a button that you press that allows you to run the PTO without being in the seat?

When you restart it, and shuts down again, are you sitting in the seat or outside at the chipper?

If yes to both, try setting a bunch of weight on the seat.

 

[North Idaho Wolfman]

Does the seat tilt forward?
On ROPS models you tilt the seat to the steering wheel to keep it running when running the PTO and not in the seat.

 

[Derf]

Is there a button that you press that allows you to run the PTO without being in the seat?

When you restart it, and shuts down again, are you sitting in the seat or outside at the chipper?

If yes to both, try setting a bunch of weight on the seat.

I haven't had to press anything, just move the PTO lever to the operating position while standing outside the cab. Since it runs for awhile, it doesn't seem to need any weight on the seat.

 

[Derf]

Does the seat tilt forward?
On ROPS models you tilt the seat to the steering wheel to keep it running when running the PTO and not in the seat.

When you don't tilt the seat forward, does the PTO not even engage? Or does it run for awhile (sometimes 45 minutes) before stopping?

And does not tilting the seat cause the engine to quit, or just prevent the PTO from engaging?

 

[Russell King]

The PTO safety system should be shutting your tractor down immediately if you are not in the seat and the PTO is on.

Therefore, you have something going on with the PTO safety system that delays the shutdown but eventually does shut your tractor down.

There must be some way to tell that PTO safety system that you are leaving the seat but need the PTO to continue running. Kubota has a couple of different ways to tell the tractor that. Two of those methods were stated above.

Please try the method that @North Idaho Wolfman suggested and see if the tractor runs continuously with the rear PTO turning.

You might tell @North Idaho Wolfman the tractor serial number and he might be able to look up how Kubota designed the tractor you have. We don’t really know if the cab is original or an aftermarket version from where we are.

 

[North Idaho Wolfman]

When you don't tilt the seat forward, does the PTO not even engage? Or does it run for awhile (sometimes 45 minutes) before stopping?

And does not tilting the seat cause the engine to quit, or just prevent the PTO from engaging?

No the seat tilted forward should allow the PTO to be engaged and allow the tractor to continue to run.
My though might be a slow reaction of the seat switch is causing a weird shut down situation.