BX 23 won't turn off!!

[Don Ricardo]

OK...I have had lots of experience with things that won't start...tractors, jeeps, the coffee pot..lots of things. But yesterday I had a real problem with my brother-in-laws little BX-23. We had been using the hoe to dig a small trench and it was time for lunch. Flipped the seat around, turned the key to "off" and nothing happened...the BX-23 kept running. I fiddled with the key, no luck. Disconnected the battery...she kept on running. Took out the fuses I could find, no luck. Pulled apart all of the molex connectors i could reach, she kept on running. In desperation I tried pinching off the fuel lines but she kept on going. My last idea short of letting her idle though a half a tank of fuel was to try cutting off the air...disconnected the air hose and put my hand over the hose and she died a quick and painless death.

Now the question is what is the problem. I used my ohm meter to check the ignition switch and I can see it open and close on start, run and off so I think that is OK. ANy ideas? I am thinking I have a stuck relay somewhere but do not currently possess any type of service manual or wirirng diagram and don't have a clue where to look for any type of relay.

Any suggestions would be appreciated.

Don Ricardo

 

[CobyRupert]

Little off topic, but can you stall a hydro if you put it in high range, low idle and stomp the pedal?

This thread, post #25 has BX 23 electricl diagrams: http://www.tractorbynet.com/forums/kubota-owning-operating/121576-bx23-solenoid-location-3.html

 

[diesel lover]

OK...I have had lots of experience with things that won't start...tractors, jeeps, the coffee pot..lots of things. But yesterday I had a real problem with my brother-in-laws little BX-23. We had been using the hoe to dig a small trench and it was time for lunch. Flipped the seat around, turned the key to "off" and nothing happened...the BX-23 kept running. I fiddled with the key, no luck. Disconnected the battery...she kept on running. Took out the fuses I could find, no luck. Pulled apart all of the molex connectors i could reach, she kept on running. In desperation I tried pinching off the fuel lines but she kept on going. My last idea short of letting her idle though a half a tank of fuel was to try cutting off the air...disconnected the air hose and put my hand over the hose and she died a quick and painless death.

Now the question is what is the problem. I used my ohm meter to check the ignition switch and I can see it open and close on start, run and off so I think that is OK. ANy ideas? I am thinking I have a stuck relay somewhere but do not currently possess any type of service manual or wirirng diagram and don't have a clue where to look for any type of relay.

Any suggestions would be appreciated.

Don Ricardo

On many diesel engines there is a fuel shut off solinod. This pulls a shutoff lever right at the engine's fuel injection pump. You can manually override these by removing the linkage, and simply moving the position from run to off. The solinods can get stuck/ seized or burn up.

Diesel engines shut off by cutting off the fuel supply. Removing fuses etc will not help. Gasoline engines shut off by removing the power to the spark plugs. These magnetic solenods replace the "fuel shut off" cable operated systems seen on older tractors but they operate the same exact way for the most part.

The last part where you cut off the air supply was THE BEST way to alternatively shut off a diesel engine. Some diesel engine runaways are caused by the engine running from the engine oil in the crankcase so the only way to shut them off is by cutting off the air supply. Please next time use something flat like a clipboard, small piece of plywood, etc instead of your hand.

Look at the fuel system and identify the fuel shut off. Good luck

 

[skyhook]

I agree with DL, "never" put your hand over the air intake on a diesel,
your lucky it was only a little 3 cylinder, those intakes can suck a hand or fingers up in no time.
A "flat board" as stated is the way to shut off the "air" supply.
Also keep in mind, these diesels will run off any type of vapor in the air thats combustible.
A gas leak, corn vapors etc, his location may have had something to do with it.
But it was most likely a problem in the "fuel shut off" at the injection pump.
Check the linkage, etc, at the pump. IMHO

 

[V1Rotate]

The fuel shutoff solenoid is probably bad. When you turn the key to the off position, you are sending 12 volts to the solenoid which causes it to close the fuel shutoff. After about 5 seconds, the 12 volts is removed and the valve re-opens. This allows the engine to come to a stop, and because the power was then removed it prevents the battery from being drained while the machine is not running.

 

[zoltanthegypsy]

Agree with V1Rotate. It's also possibly a bad connection or a bad fuse. That happened on my GR2120 when a defective light wiring harness shorted and blew a fuse. Same fuse was used by the shut-off solenoid. On that machine - and my BX24 IIRC - one can manually move the shut-off plunger without disconnecting anything.

Z.

 

[J_J]

Seems to me that most fuel solenoids would have no flow until voltage is applied, and when you remove voltage, the solenoid closes, shutting off the fuel flow.

Could be wrong, so everyone recheck your shut off voltage to see if the engine runs with voltage aplied and quits when voltage is removed.

I actually have a pull lever to shut off the fuel to the fuel pump.

 

[Tomtint]

This happened to my BX22 and also my fathers BX23. There is a fuel shut off on the left side of the motor . Very low down on the front. It is difficult to see if you don't know what you are looking for. If I remember correctly it was easier to push the lever from up behind the LF wheel. I believe it was caused from a bad solenoid or weak battery.

 

[V1Rotate]

It's my understanding (and I could be wrong) that these fuel solenoids are designed to be "fail safe".
Meaning that because the solenoid needs no power, if the electrical system should fail, you can still get the machine back home.

 

[David_Kb7uns]

Seems to me that most fuel solenoids would have no flow until voltage is applied, and when you remove voltage, the solenoid closes, shutting off the fuel flow.

Could be wrong, so everyone recheck your shut off voltage to see if the engine runs with voltage aplied and quits when voltage is removed.

I actually have a pull lever to shut off the fuel to the fuel pump.

Most of the Kubota small diesel engines have an external keystop solenoid, power must be applied to pull the stop lever on the rack to shut off the engine. If you do not believe it go find a BX with a D902 engine and watch the solenoid when you turn the key off and then wait for the keystop timer to time out and release the solenoid.

Everybody with a diesel engine needs to learn how to manually actuate the fuel stop lever on the pump.

Some of the larger Kubota engines have a solenoid that is bolted to the block and actuate the rack internally and have 3 wires with a run or hold open coil and a stop coil.

David Kb7uns