I have checked everything I found in wiring diagram that ties into solenoid.The solenoid has 3 wires that plug to it.2hot wires & 1ground , but the funny thing is the 2 hot wires tie together just before they get to the soleniod.10 seconds after the tractor started the solenoid is to hot to touch
In re reading your post several times I was puzzled by your comment that although the solenoid had two power wires and a ground wire, the two power wires were joined together a short distance from the solenoid.
I am lucky to have a Kubota WSM in pdf form because you are able to blow up individual devices and actually see how they work inside. With the normal paper wiring diagram, because you are looking at a printed page, there is nothing you can do to expose the tiny details inside a device.
I have marked up the fuel stop solenoid and associated wiring so I can explain what is happening.
The two power wires are tied together because the switch to shut off the pull in coil is inside the solenoid and controlled by the movement of the solenoid push-pull rod.
The internal contacts are pointed to by the red line. The two tiny dots are the two pull in coil switch contacts and the bar between them with the push-pull rod attached is the switch itself.
The hold and pull in coils are powered any time the ignition switch is in any position except off. It is getting power with the key on, with the key in glow, or with the key in start.
The pull in coil is powered at exactly the same time. However it can shut itself off by moving its push-pull rod in the direction of the red arrow pointing up.
If the push-pull rod cannot move, the pull in coil stays energized.
The ignition switch schematic shows the fact that the stop solenoid is is powered in the key positions and also even as the key switch passes between positions so there is no opportunity for the solenoid to retreat between key positions.
My suggestion is to disconnect the solenoid push rod from the injection pump and see if the push-pull rod moves easily by hand. If the pull in coil switch contacts inside the solenoid have become welded together the push rod wont want to move. If it does not move, power will continue to flow to both coils inside the solenoid creating intense heat quickly.
If the push-pull rod will move manually, see if it will move when you put the key to on. It does not have to go to the start position as it is getting power in the on position.
The push-pull road should move and the solenoid should only get warm.
If you have a multi-meter, set it to ohms and connect it to the two power terminals on the solenoid itself with the wiring harness disconnected from it. With the meter providing a steady reading, which will be the combined resistances of both the pull in and the hold coils, push in the push-pull rod and the ohms reading should go to 0 as the internal contacts have opened and there is no longer a circuit. If there is no change in the ohms reading there is an internal problem.
Another poster has suggested a weak battery may be to blame and while I agree that is possible, lets see what these simple test reveal. Now that we know that the solenoid should have been pulled in the instant you turn the key to on and long before you get to start I am hesitant to accept the weak battery possibility.
If you don't understand what I am saving, post again or go to my profile and send me an email not a private message. We can even arrange to talk on the phone.
Dave
M7040