Help -- L5030 stop solenoid behaving badly

[jjmellon]

One day last week my tractor wouldn't start. It cranks and begins to run, then dies after one or two seconds. With the stop solenoid removed, it starts fine. I tested the solenoid outside the tractor, and energizing either pin caused it to retract (as it's supposed to). I convinced myself that none of the safety switches were bad (e.g. PTO switch and HST accel pedal switch block the starter motor when on (which isn't happening), seat switch supposedly is bypassed if tractor is in neutral). So, out of ideas, I decided to replace the solenoid in case it had some erratic behavior. Unfortunately, the brand new solenoid behaves exactly the same.

I now paid closer attention to what happens when I turn the key. When I turn it to "On", the solenoid clicks once, then clicks again about two seconds later. If I then move the key from "On" to "Start", the engine won't even begin to fire. However, if I quickly move the key from Off to Start, the engine will start and run for about one or two seconds, then die.

So it seems to me that the solenoid is first being retracted in the On position, then released after about two seconds. This happens with the new solenoid too.

Any idea what could cause this behavior?

 

[Rocky Hoffler]

If new part is acting the same as old part I would look elsewhere could ignition switch be the problem especially if you are sure of safety switches I would check them again including pto

 

[KennyV]

Is your fuel solenoid a kill solenoid or a hold fuel on solenoid.
Most are kill solenoids, that is they are not energized until the key switch is turned to Off. Then a timer relay supplies 12 volts to the solenoid for a few seconds. after that it times out and will do nothing until it is time to shut off the fuel. The fuel shutoff returns to fuel On after every kill cycle.

The hold on type has two coils built into it, a pull coil (draws about 10 amps), and a hold coil (draws only a couple amps)... This type fuel shut off is Always in the Off position except during start and run....

 

[kuboman]

It won't be any of the safety switches, as they will not allow the starter to energize. You will likely have a 3 wire plug to the solenoid. You need to check that you have power to both the terminals. One will be ground and 2 power. One powers the energizer coil the other powers the hold on circuit. My guess is you have a bad connection somewhere in the hold on circuit.

 

[skyhook]

Start by checking the fuse that powers that circuit, (solenoid).
Check both ends of the fuse for corrosion and the clips it lock's into,
go from there, as stated, it does sound like a poor connection somewhere.

 

[jjmellon]

Thanks for the advice. My tractor has a two wire stop solenoid, where the rod is supposed to retract (allowing fuel to flow) when a pin is energized.

I tested the solenoid's operation when removed from the fuel pump but still connected to the tractor's wiring harness, so I can see exactly what happens. As I suspected, with the key at "On", the rod is retracted but then is released after about two seconds. I then tested the wiring connector with a meter. It seems that at "On", one of the pins goes to 12 volts, then within about a second drops back to 0. The other pin is not energized at "On" or "Start".

 

[jjmellon]

I've been told by a Kubota tech, based on my description, that it's the OPC Timer -- a relay that (when working) inserts a 1 second shutoff delay when the seat safety switch and PTO switch are both on. Searching online, replacing this part has fixed several cases where Kubota tractors intermittently shut off. Since the brief version of my problem is "shuts off with a one second delay right after starting", it sounds plausible.

I've ordered the part.

 

[kuboman]

Sounds like you may have it diagnosed. Good luck let us know how it works out.

 

[jjmellon]

I got the OPC Timer and installed it -- problem solved.

 

[Rocky Hoffler]

Good on you:cool2: