Oil & Fuel Tractor turns over but won't start?

Boris1 · Apr 22, 2012

k0ua said:
I don't know for sure how they work, and they may not all be the same, But If I was designing it, it would work this way, The key would apply power, and the fuel solenoid would energize and stay that way with coil drawing a small amount of power to create the magnetic field enough to draw back the armature and overcome the spring pressure pushing the armature the other direction. When the key is shut off, the voltage is removed,the magnetic field collapses and the spring pressure pushes the solenoid into the injector blocking fuel flow. Does it actually work this way,? I don't have a clue. Perhaps someone who actually knows can comment.

Boris1 something you said bothers me, you said:

So I went back and connected the solenoid back up and by the time I got to the other side of the tractor I heard it pull in? I guess it was a bad connection,

the thing that bothers me if I understood you correctly, is the solenoid pulled in after a few seconds after you put the connector back on the solenoid.. The problem with that is it should have pulled up instantly when you reconnected it. I am thinking you still have an intermittant open connection near that connector, in that connector or perhaps the inside connection of the very small guage wire the solenoid is wound with when it attaches to the actual terminals the connector attach to. So if you still have a problem it will manifest itself when you least want it or need it. Could it be possible you had a little corroision on the terminals of the plug? maybe a little dielectric grease (silicone) on those would help, You can hope that is all it is. Time will tell, but at least you now know where to start looking for trouble if it comes back. Now if it were me, I would take voltage readings and make a resistance check (ohms) of that coil while it is working for reference if it quits again..Good Luck

James K0UA

Will do and thanks again for the insight!

Matt

RaydaKub · Apr 22, 2012

k0ua said:
I don't know for sure how they work, and they may not all be the same, But If I was designing it, it would work this way, The key would apply power, and the fuel solenoid would energize and stay that way with coil drawing a small amount of power to create the magnetic field enough to draw back the armature and overcome the spring pressure pushing the armature the other direction. When the key is shut off, the voltage is removed,the magnetic field collapses and the spring pressure pushes the solenoid into the injector blocking fuel flow. Does it actually work this way,? I don't have a clue.

I was in your camp, but I've come to see the light after a rather loud Kubota thread about "my tractor won't shut off" last fall. If you have a load on and the fuse blows, the tractor shuts off and the load is still rolling. Not good. Usually this is going to be more serious than the engine just not shutting off. You should still be able to turn off the pto and leave the engine running in an emergency for example. So the default is that the energized position is to shut it off and only momentary. Less draw for current all during this time leaves less wear on the electronics also.

k0ua · Apr 22, 2012

RaydaKub said:
I was in your camp, but I've come to see the light after a rather loud Kubota thread about "my tractor won't shut off" last fall. If you have a load on and the fuse blows, the tractor shuts off and the load is still rolling. Not good. Usually this is going to be more serious than the engine just not shutting off. You should still be able to turn off the pto and leave the engine running in an emergency for example. So the default is that the energized position is to shut it off and only momentary. Less draw for current all during this time leaves less wear on the electronics also.

Yep I believe you are right, I have looked at some bits and pieces of other threads, and there is a timer relay, Not sure how the timing is achieved yet, it might be a time delay relay complete as a componet. or something else that controls it, but in typical automotive design, they try to make it a simple and cheaply as they can. I am not 100 percent sure why it clicks when you energize the circuit, but it might just cycle and return to the relaxed position which allows fuel flow, then the timer relay is set and ready to go, when power is removed from circuit, the timer relay applies battery voltage for a few seconds to the solenoid and then it is relaxed. All supposition on my part, but sounds reasonable. And so does your explaination of why not just hold the relay back with voltage and let it snap shut to shut off the fuel. Your runaway scenario was not a pretty one

And I am sure that happened to someone a long time ago before they came up with this idea.

James K0UA

jimbo64 · Apr 22, 2012

Since its under warranty i would have your dealer make note of the fact you had a prob and what the fix was--if it does it again you may need parts----j