Why did my tractor start?

[frogpond]

I don't understand... I have a Kubota BX25D, about 1500 hours. Today I worked it for several hours, using the loader and the backhoe to extract a stump and move dirt, roots, etc. Temp in the low 40s, no rain.

I started (normal, no hesitation) and stopped it several times while using saws, eating lunch. After half-hour lunch break, I drove it back to the work site and turned it off. A few minutes later it refused to start. It clicked, you could hear the fuel pump working, but it wouldn't crank. The lights worked, and I held it for the glow plug, but still nothing. Tried the key while manually pushing the switch under the seat, made sure the transmission was in neutral, made sure the pto lever was off, checked the rocker pedal to confirm neutral...still nothing. Checked the battery: 12.71 volts.

Finally I got my amateur mechanic neighbor to look at it. He poked around, and finally jiggled the loader joystick, and then it started! He had no idea why. I drove it back to the shed, turned it off. Started fine again. While running, the battery was showing 14.2 volts at idle, so it's charging fine.

The only other possibility is something to do with the 3rd function setup, a kit from Summit, which I added last summer to run an Add a Grapple, which I attached to the loader bucket. It's controlled by 2 buttons on a
replacement handle on the loader joystick. The wire runs down the joystick shaft to the solenoid. Could the problem be related to that?

I'm happy that the tractor is behaving again, but it would be nice to know why. All opinions are welcome.

 

[plastikosmd]

I’m not sure but I learned a new technique. Generally, I start with the hammer and start hitting things. I will now start with the jiggle then move to the hammer…

 

[Jerry/MT]

I don't understand... I have a Kubota BX25D, about 1500 hours. Today I worked it for several hours, using the loader and the backhoe to extract a stump and move dirt, roots, etc. Temp in the low 40s, no rain.

I started (normal, no hesitation) and stopped it several times while using saws, eating lunch. After half-hour lunch break, I drove it back to the work site and turned it off. A few minutes later it refused to start. It clicked, you could hear the fuel pump working, but it wouldn't crank. The lights worked, and I held it for the glow plug, but still nothing. Tried the key while manually pushing the switch under the seat, made sure the transmission was in neutral, made sure the pto lever was off, checked the rocker pedal to confirm neutral...still nothing. Checked the battery: 12.71 volts.

Finally I got my amateur mechanic neighbor to look at it. He poked around, and finally jiggled the loader joystick, and then it started! He had no idea why. I drove it back to the shed, turned it off. Started fine again. While running, the battery was showing 14.2 volts at idle, so it's charging fine.

The only other possibility is something to do with the 3rd function setup, a kit from Summit, which I added last summer to run an Add a Grapple, which I attached to the loader bucket. It's controlled by 2 buttons on a
replacement handle on the loader joystick. The wire runs down the joystick shaft to the solenoid. Could the problem be related to that?

I'm happy that the tractor is behaving again, but it would be nice to know why. All opinions are welcome.

I'd look for a loose wire to the starter solenoid near the joystick cables.

 

[Gordon Gould]

If battery is good and it clicks and doesn't crank and the fuel pump runs that means it wants to crank but can't. Look for a loose connection between battery posts, solenoid, starter, and battery ground. Or could be a bad solenoid or bad spot in starter. It will most likely come back again.

gg

 

[dougtrr2]

I would start with the PTO engagement lever switch. Mine got a little out of adjustment. Sometimes it would start, sometimes it wouldn't. The quick "fix" was to let the lever snap back to the off position. The permanent fix was to readjust it.

Doug in SW IA

 

[lpakiz]

If you suspect poor battery cable connections, one last-ditch test is to just hold the key in the start position for a while-10-20 seconds. Then go around and feel the battery posts, starter solenoid connections, the short jumper strap that carries power from the outbound solenoid terminal to the big stud that takes power into the starter motor, everywhere the big cables carry power.
Many times, a bad connection will be warm, hot, or smoking.
Occasionally, the poor connection will arc enough to jump the rust or corrosion and deliver enough amps to actually start the engine, maybe several times, then it will fail again.

 

[frogpond]

Thanks to all! These sound like logical ways to proceed. I won't be able to follow them up until next weekend, but then I'll be sure to report back.

 

[4570Man]

I’d be more inclined to go with a loose connection on battery cables somewhere but potentially the 3rd function had gotten engaged and the starter wasn’t strong enough to turn it with the pump deadheaded.

 

[bmaverick]

Does this machine have a FOB for remote start? If so, check the controller and relay.

 

[frogpond]

No remote start capability. I didn't even know that exists for tractors.

 

[frogpond]

I’d be more inclined to go with a loose connection on battery cables somewhere but potentially the 3rd function had gotten engaged and the starter wasn’t strong enough to turn it with the pump deadheaded.

Hmmm...I suppose I might have pushed one of the 3rd function buttons by accident. How could I test this theory?

 

[lpakiz]

I think that if it's resistance via the hydraulic system, (the third function idea) that you could observe a slight movement of the fan/alternator belt during a start attempt. Have someone hit the starter while you watch for movement.
PS. I don't have a third function, not positive how they work, but I assumed that the switch was a "momentary contact" button. If so, it could only cause hydraulic lock when activated.
When not activated, doesn't the function return to the spool valve (joystick) itself?

 

[frogpond]

I think that if it's resistance via the hydraulic system, (the third function idea) that you could observe a slight movement of the fan/alternator belt during a start attempt. Have someone hit the starter while you watch for movement.
PS. I don't have a third function, not positive how they work, but I assumed that the switch was a "momentary contact" button. If so, it could only cause hydraulic lock when activated.
When not activated, doesn't the function return to the spool valve (joystick) itself?

Yes, they are momentary contact buttons.

 

[JasperFrank]

How did you test voltage? Across Batery Terminals + and -, or Across Termial + and a frame ground point? The clicks that you heard, was it the starter solenoid? This would rule out any of the safety switches.

 

[bmaverick]

No remote start capability. I didn't even know that exists for tractors.

that's been out there since early 2000s. I have remote start on my genset too.

 

[frogpond]

Tested across battery terminals. I thought the clicks were fuel pump.

How did you test voltage? Across Batery Terminals + and -, or Across Termial + and a frame ground point? The clicks that you heard, was it the starter solenoid? This would rule

 

[rScotty]

I would start with the PTO engagement lever switch. Mine got a little out of adjustment. Sometimes it would start, sometimes it wouldn't. The quick "fix" was to let the lever snap back to the off position. The permanent fix was to readjust it.

Doug in SW IA

That's one of the things I would look at. Basically look at all the "safety" no-start switches and their wires. My seat has two of those switches, the PTO one, the clutch has one, the hand brake has one, and I'm sure that there are more. Every one of them has an adjustment. Last time mine wouldn't start it was one of the seat switches....actually it was the wire to a seat safety switch which had migrated over to the seat spring so that when I sat down in the seat the the safety switch actuated properly and the engine started, but then later on when I shiftted positions the current through that switch was shorted to ground by the seat spring - which blew the fuse.

So the symptoms were that the tractor would be working fine when for no particular reason the motor would stop. And then the starter wouldn't re-start it. Investigation showed all the safety switches were fine, but a fuse was blown. I'd replace the fuse and all would be fine for awhile until the motor stopped again. Another fuse. Again and again.... until I just happened to notice that seat switch wire...

rScotty

 

[frogpond]

That's one of the things I would look at. Basically look at all the "safety" no-start switches and their wires. My seat has two of those switches, the PTO one, the clutch has one, the hand brake has one, and I'm sure that there are more. Every one of them has an adjustment. Last time mine wouldn't start it was one of the seat switches....actually it was the wire to a seat safety switch which had migrated over to the seat spring so that when I sat down in the seat the the safety switch actuated properly and the engine started, but then later on when I shiftted positions the current through that switch was shorted to ground by the seat spring - which blew the fuse.

So the symptoms were that the tractor would be working fine when for no particular reason the motor would stop. And then the starter wouldn't re-start it. Investigation showed all the safety switches were fine, but a fuse was blown. I'd replace the fuse and all would be fine for awhile until the motor stopped again. Another fuse. Again and again.... until I just happened to notice that seat switch wire...

rScotty

But in my case, it started again without changing a fuse. However, I will check the safety switches again. Thanks for the suggestion.

 

[frogpond]

Well, back at the tractor today...and of course, it refused to crank. Just a click, then the whirring of the fuel pump. Then, after I turned off the key, another decisive click. Checked to make sure the pto lever was in neutral, and that the foot rocker pedal was neutral.

So then I started in on electrical cables and connections, as suggested. First extracted the battery from its little cave, disconnected the cables, cleaned the terminals, cleaned the posts to bright metal, reconnected. And it eagerly roared into life!

I'm glad it was that simple, and I'm a little embarrassed too. Even though the voltage was okay, both terminal to terminal and terminal to ground, somehow that juice wasn't making it to the starter. I hope it will start again tomorrow.

My thanks to all of you who helped!

 

[lpakiz]

The "somehow" is simply that the amps could not consistently jump the poor battery connection when you called for them. If you didn't, clean the other ends of the big cables, too.
The click AFTER you turned OFF the key could be the "shut-down" solenoid/relay.
That device gets energized for a few seconds when you return the key to OFF. You don't hear it energize because the engine is running but you hear the relay "drop out" after the timer expires, usually several seconds later.
BTW, a D4 Caterpillar works the same way.