The machine starts fine but it just suddenly started to not shut off using the ignition. I have tried everything and to no avail. I have bench tested the stop solenoid. The ignition, replaced last year, works. I have tested the relay; that works (also replaced just a year ago). I have checked all fuses and the battery is virtually new. Has anyone got any ideas? I could be really grateful for any pointers.!
Kubota bx2350 wont turn off
- Thread starter Kip
- Start date
LazyGear
Well-known member
- Joined
- Oct 10, 2025
- Messages
- 51
It seems like the stop circuit is still receiving voltage even when the key isn’t on. I’d recommend looking for a short to ground or checking if there’s a wiring harness problem at the solenoid or ignition switch. Don’t forget to check any inline kill switches or connectors, as those can sometimes fail unexpectedly
- Joined
- Feb 21, 2025
- Messages
- 325
I’m no expert, but I did a bit of research and hope this helps.
Yes, this is a common issue with BX-series, including the BX2350, and you’re on the right track. Since it runs with the key off and only stops when you turn the fuel knob, that really streamlines the possibilities.
Here are the most likely reasons, ranked by how often they occur:
1. Alternator backfeed (very common on BX tractors)
If there's a problem with a diode inside the alternator, it can send voltage back into the ignition circuit, keeping the stop solenoid energized even when the key is off.
Quick check: unplug the alternator while the engine is running and then turn the key off.
If the engine shuts down normally, the alternator is likely the issue.
2. Stop solenoid receiving constant power
It might test fine but could still be getting power when it shouldn't be.
Check the voltage at the solenoid with the key OFF.
If you see 12V, you’ll need to look for a short or backfeed.
3. Ignition switch circuit backfeed
Even if the switch tests “good,” it might not completely isolate the circuits inside.
Make sure to check for continuity on all terminals in the OFF position.
It’s a good idea to compare your findings to a wiring diagram.
4. Safety interlock circuit (PTO or seat switch)
On BX models, some shutdown logic runs through safety circuits.
A stuck relay or damaged wiring near the PTO or seat switch can lead to unusual behavior.
As a test, you could try disconnecting the seat switch.
5. Ground issue
Weak grounding can cause the current to take unintended paths.
Carefully inspect the engine block ground strap and other frame grounds.
Based on what you're experiencing, starting with the alternator unplugging is recommended. It’s a quick test and often resolves many of the “won’t shut off” issues with BXs.
What you’re facing is definitely an electrical backfeed, not a fuel or mechanical problem.
Yes, this is a common issue with BX-series, including the BX2350, and you’re on the right track. Since it runs with the key off and only stops when you turn the fuel knob, that really streamlines the possibilities.
Here are the most likely reasons, ranked by how often they occur:
1. Alternator backfeed (very common on BX tractors)
If there's a problem with a diode inside the alternator, it can send voltage back into the ignition circuit, keeping the stop solenoid energized even when the key is off.
Quick check: unplug the alternator while the engine is running and then turn the key off.
If the engine shuts down normally, the alternator is likely the issue.
2. Stop solenoid receiving constant power
It might test fine but could still be getting power when it shouldn't be.
Check the voltage at the solenoid with the key OFF.
If you see 12V, you’ll need to look for a short or backfeed.
3. Ignition switch circuit backfeed
Even if the switch tests “good,” it might not completely isolate the circuits inside.
Make sure to check for continuity on all terminals in the OFF position.
It’s a good idea to compare your findings to a wiring diagram.
4. Safety interlock circuit (PTO or seat switch)
On BX models, some shutdown logic runs through safety circuits.
A stuck relay or damaged wiring near the PTO or seat switch can lead to unusual behavior.
As a test, you could try disconnecting the seat switch.
5. Ground issue
Weak grounding can cause the current to take unintended paths.
Carefully inspect the engine block ground strap and other frame grounds.
Based on what you're experiencing, starting with the alternator unplugging is recommended. It’s a quick test and often resolves many of the “won’t shut off” issues with BXs.
What you’re facing is definitely an electrical backfeed, not a fuel or mechanical problem.
