Hello louieRD, another slim possibility could be a clogged fuel filter or some other sort of fuel restriction. Or, if this system has a breather associated with the fuel tank and it is plugged, it could possibly starve it out after it develops enough vacuum to curtail fuel transfer/flow. Engine and fuel system type could render these lines of logic possible or unlikely depending on a number of different variables.

I have had engine issues with a number of different types of equipment over the years, foreign objects in the fuel tank have posed problems similar to this. Engine runs until the supply fitting from inside the tank is blocked and all of the sudden the engine quits, suction relaxes, object moves away, and then the same thing happens again after starting and running the engine. This scenario is generally more intermittent but that isn't a guarantee as such.

As I am typing this I can't remember whether this is a diesel or a gasoline engine, regardless, changes in fuel, additives, and other chemical additions could possibly cause degradation of seals, o-rings, gaskets or other components and have effects that could result in poor engine performance. Good luck and regards, Allan

Like Allan has said check your fuel system.  If it has fuel transfer pump check it out to be sure it's getting enough fuel to injection pump and nothing plugged up along the way.  Sounds like something plugged up or transfer pump has gone out to me.  If has check valve somewhere that is okay not leaking back or plugged up.  Check terminal on shut off switch on injection pump that is hasn't gone bad too.  Call Lincoln or Bill's in OKC with your code number and ask for a manual on your Kubota.  I'm about sick of Lincoln can't put stuff back on their site for everyone to access and if the one with Kubota is on there they got it hid again lol.

www.lincolnelectric.com

www.billswelderrepair.com