2006 bx24 wouldn't shutdown

[vstah]

2006 bx24 would not shut off using the key switch. Ended up disconnecting battery. Any harm done? What's next? New key switch?
Fuses all good. Solenoid shut off? How to determine?
Thanks in advance

 

[PaulL]

Without knowing your level of knowledge, the basics here are:

1. A diesel engine doesn't require electricity to run because there's no spark plugs - as long as it has fuel it'll keep running
2. To stop them they have a fuel cutoff solenoid. So when you turn the ignition off it's going to cut fuel to the motor to stop it running
3. On the small Kubotas some have a solenoid that has to remain powered to let fuel through, when power is cut off the solenoid automatically closes. I'm guessing you have this, as disconnecting the battery stopped the motor
4. I believe other Kubota tractors have a solenoid that needs to be powered to cut off the fuel - so when you turn the ignition off that actually powers the solenoid for a period of time to stop the motor. I'm assuming you don't have this configuration

So, if we assume you have a solenoid that needs to be powered in order for fuel to flow, then that solenoid must have been getting power after the ignition was switched off. That would suggest a problem with the ignition, but could also be a short somewhere.

I think the diagnosis path is to find the solenoid, and check with a volt meter when it's powered and when it's not (you might be able to just turn the ignition on without starting it, and see whether it gets powered.....but the behaviour can be different between when the motor is running v's not).

If you've identified the solenoid and worked out how it's getting powered, then you can manually stop the motor by (powering/disconnecting) the solenoid as appropriate.

Then it's a case of following wires and using a voltmeter to work out what's happening. If there's still power on that solenoid when the ignition is off, but when you cut the power the motor stops, that'd be a strong pointer at the ignition switch.

 

[Russell King]

2006 bx24 would not shut off using the key switch. Ended up disconnecting battery. Any harm done? What's next? New key switch?
Fuses all good. Solenoid shut off? How to determine?
Thanks in advance

There is probably some sort of manual shutoff system that would work for shutting off the tractor.

You could also use the operator present in seat safety switch and stand up and then press the hydrostatic pedal to move forward or in reverse. That should shut your tractor down but may not work if the shut down solenoid is defective.

You should read the operating manual for locating the manual shutdown.

if you don’t have one look here for one =Kubotabooks dot com

 

[jaxs]

There is probably some sort of manual shutoff system that would work for shutting off the tractor.

You could also use the operator present in seat safety switch and stand up and then press the hydrostatic pedal to move forward or in reverse. That should shut your tractor down but may not work if the shut down solenoid is defective.

You should read the operating manual for locating the manual shutdown.

if you don’t have one look here for one =Kubotabooks dot com

I have questions about the system Kubota uses to kill their engines and you seem to understand. Is it true a rod extending from solenoid to dash could manually do what those electric devices do? If that's true,how/why is it safer to use electric devices instead of manual means? Sorry if I'm missing the obvious but I just don't understand it.

 

[Russell King]

I have questions about the system Kubota uses to kill their engines and you seem to understand. Is it true a rod extending from solenoid to dash could manually do what those electric devices do? If that's true,how/why is it safer to use electric devices instead of manual means? Sorry if I'm missing the obvious but I just don't understand it.

I understand the general principles that are used to stop a diesel engine from running and @PaulL described them above. But basically remove fuel, remove air or remove compression and the d engine will not run.

In the older tractors like my L185 the key could be turned off and the tractor would still run. There was a manual lever that worked with the throttle linkage to push the rack in the injection pump to a spot that basically removed the ability to supply fuel to the injectors and therefore into the cylinders of the engine. In short you pulled the lever manually to shut the tractor down.

I’m not sure when exactly but the ability to shut the tractor down was needed to increase safety. For instance on my tractor the only safety switch was on the clutch pedal so the trac would not crank the engine unless the clutch pedal was depressed. I imagine that some people would stand beside the tractor and would push the pedal down by using a hand and then start the tractor. Then they could release the pedal and get run over if the tractor was in gear. So the manufacturer added a switch to the seat so it had to be depressed for the tractor to run.

The mechanism was still the same to shut down the engine- shut off the fuel delivery but now it was electrically driven by a solenoid instead of the lever. The manufacturer still provides a manual method for safety reasons. Originally it was a pull knob on the dash but now it is normally down by the injector pump itself and the solenoid is usually attached to the same mechanism.

Another way that is more failsafe is to load the off position with a spring and push the lever into the run position. That way if the solenoid fails the tractor will die by the spring force pulling it into the non running position.

So there are two different methods used with the solenoid and Kubota uses both of them. I don’t know why the don’t fix on one but it may have to do with the injector pump size or the expected users of a particular machine.

I hope I answered your question but I don’t know exactly how your machine works to shut it down normally. Removing the power supply may have actuated the solenoid or it may have removed power to a “computer“ that controls the engine operation.

I will look at the illustrated parts list for your tractor to at least give you an idea of what you should be looking for and post that.

 

[Russell King]

Here is the manual stop lever. Looks like it is front of engine on upper right (sitting in the seat) side. There is also a solenoid that I will post separately.

 

[Russell King]

Here is the solenoid and this one shows that there is a knob on the dash that is pulled to shut down the tractor

 

[DustyRusty]

Replace the stop solenoid. They do go bad over time. The only reason that the engine shut down when you removed the battery cable is because it ran out of fuel. The fuel pump is electric. You can get the shut-off solenoid on eBay for less than at the Kubota dealer. Locate it on your engine, and test it with a multimeter. You can also test to see if it is getting power to operate. It could be as simple as a blown fuse. I replaced the one on my BX22 after the same thing happened to me. I have replaced the stop solenoid on my Lister Petter generator twice in 15 years. Now I keep a spare on hand for the generator.

 

[lugbolt]

the early models used a shutoff solenoid mounted on the top of the engine, two 10mm head bolts holding it down. Those types required 12v to pull the fuel lever in to stop the engine. This also required a module to make it happen (combination box). The combination box is a high failure rate item. So is the solenoid itself.

In the old days you had no shut off, it was manual (lever you pull out on). If you rolled the tractor over it would not shut off until the fuel pickup became uncovered and the fuel line ran completely dry....took a while. Then they started using these electric solenoid things like I've described, which was failure prone, along with it's control mechanism. If it were me, I'd replace the solenoid and combination box. Both have new part numbers. Be sure to adjust the solenoid properly as the holes are oblonged (at least oem stuff is) so you can slide the solenoid back & forth just a little bit to make the adjustment.

--but wait. Remember, the government likes clean air. Keep this in mind. In years past a lot of equipment had a "road draft tube", basically a crankcase breather vent tube that ran from the valve cover toward the ground, which vents crankcase vapors. Can't do that anymore so now they have to re-route the vapors back into the engine to be re-burned. Closed crankcase ventilation. Clean air. If one were to roll the tractor over, sometimes the oil in the crankcase is gravity fed to the valve cover area, which is then pulled into the intake manifold, and there is nothing you can do to shut the engine off at that point aside from cutting it's air supply, it is a runaway until it either runs out of oil or hydraulically locks the engine. Kinda ironic how "they" solved "their" problem and created another. I'm not saying it's good bad or otherwise, just saying that's how it works. You wouldn't believe how many engines I've had to replace because of this...a bunch of them. Surprised nobody got hurt in some of the runaway situations, especially when mowing or tilling.

I kind of wish they'd put a air valve in the intake for the purpose of cutting off the air supply in case of a rollover.

 

[Henro]

My BX2200, which would be the same as a BX22, and likely the same as Lugbolt described for the BX24.

There is no mechanical way to move the rack inside the injector pump to manually shut the engine down, without removing the fuel cutoff solenoid first.

Lugbolts advice is right on with respect to my BX and probably with respect to the OP's tractor.

Everything else are just valid questions from those who don't know the details of the small BX tractors. Good thoughts and information, but likely not applicable to the OP's situation.

Disconnecting the battery resulting in engine shutdown, would prove lugbolts assesment. Electrical power must have been keeping the spring loaded solenoid from shutting the engine down. Troubleshooting the things he suggested should solve the issue...