Kubota B2910 Not Starting with Ignition Key

[Jim Richardson]

Now it is my turn. Long time lurker in these forums and now I have the problem.

I have a B2100 and a B2910. The B2910 is HST and acts like there is a safety switch problem. I push in the clutch, move the two PTOs to neutral, turn the key, I get all three lights, but no starter engagement.

Here's what I was doing before the failure. I was mowing, using the orange knob handle to the right of the seat for forward speed. I normally just push the rocker pedal. I remarked to myself that the handle gets more speed than the rocker pedal does, and even pushed the rocker pedal down harder than normal. So... I naturally suspected the rocker pedal safety switch.

But I tried the easy things first. I cleaned up the battery terminals, and even tried jumper cables. I would suspect bad battery or connections if when the key is turned to start, the dash lights dim. But here, the dash lights remain steady, which I interpret to mean no starter current draw. I put an ohm meter on the 5A fuse and it is fine. I tried the spare 5A and it is fine too. I swapped them for fun. No change.

I visually inspected the three safety switches.

I started with the rocker pedal switch, as the last thing I was doing was pushing the rocker beyond where I normally put it. The rocker pedal depresses the plunger when it has no pressure. I put an ohm meter on the wiring harness connector and got continuity as the pedal sits, and I lose continuity when pressing forward or backwards.

Next I did the same to the PTO safety switch. With both PTO levers in neutral the switch plunger is depressed, and I have continuity at the ohm meter. Moving either PTO lever breaks the continuity.

The clutch safety switch had the gas tank leaning on it, and the wires were missing some insulation. I fixed the wires, but that did not solve the no crank problem. I put an ohm meter on the wiring harness connector I have no continuity as the clutch sits, and I get continuity when I depress the clutch. To me that means that all three switches work and are in adjustment.

I next pulled the wiring harnesses from the three safety switches, and one by one jumped them, tried to start, until all three were jumped. Still no starter engagement. I am stumped. What am I missing? Thanks in advance for your guidance.

PS: I did earlier in the year have a mouse nest behind the gauges, with chewed insulation, which blew the 10A fuse. That has all been cleared up. Yes, that is a 12mm socket holding the fuel tank up to give me working space.

 

[CH4Ohio]

I don't really have any bright ideas. Seems like you've eliminated the safety switches -- especially the clutch switch which is a known problem as far as working itself loose and needing adjustment.

Seems suspicious that you need to use the cruise control and say that you get better response using that handle instead of the pedal. I'd spend a few minutes trying to figure out why that is. I'm sure you've already made certain that the cruise control handle is fully back into the detent notch and isn't engaged at all.

What about at the starter? Do you get voltage to the starter when you turn the key? Can you trace the wire back from the starter and find the solenoid? Do you get voltage at the solenoid or starter relay when you turn the key?

Did you check all the fuses? Did you verify that the battery cables are tight and ground is good and tight.

Sounds like you already know all this. Just throwing out some thoughts.

Good luck with it!

 

[Jim Richardson]

I had not considered the speed control lever, as I have never used it and don't even think it is connected to the rocker pedal. So I took a look. There are two levers under the gauges: left for speed control, right for parking brake. The speed control lever is down. I can push it up, but a spring brings it back down.

Similar to the way the parking brake lever is connected to a plate with notches that hold the brake, the speed control lever has a pawl that engages a plate with four notches that is welded to the steering support. Inspection at the pawl shows that it one time did engage the top notch, but now it is not aligned to fit in any notch. And since that plate is welded, there is no way it will engage, unless I bend the pawl, which I am considering.

The lever is connected to nothing else. I looked for a rod that went down to the rocker pedal assembly, but nothing is there, and I don't see holes where something is missing. I don't see how bending the pawl to fit into a notch changes anything.

This leads me to two questions: The first question is how is the speed control lever supposed to work? Am I missing parts? The more immediate question is, with all three safety switches jumped, could the speed control even stop the starter from engaging? Thanks for your advice.

 

[CH4Ohio]

I had not considered the speed control lever, as I have never used it and don't even think it is connected to the rocker pedal. So I took a look. There are two levers under the gauges: left for speed control, right for parking brake. The speed control lever is down. I can push it up, but a spring brings it back down.

Similar to the way the parking brake lever is connected to a plate with notches that hold the brake, the speed control lever has a pawl that engages a plate with four notches that is welded to the steering support. Inspection at the pawl shows that it one time did engage the top notch, but now it is not aligned to fit in any notch. And since that plate is welded, there is no way it will engage, unless I bend the pawl, which I am considering.


The lever is connected to nothing else. I looked for a rod that went down to the rocker pedal assembly, but nothing is there, and I don't see holes where something is missing. I don't see how bending the pawl to fit into a notch changes anything.

This leads me to two questions: The first question is how is the speed control lever supposed to work? Am I missing parts? The more immediate question is, with all three safety switches jumped, could the speed control even stop the starter from engaging? Thanks for your advice.

That's the Brake Lock and the Tilt Wheel levers.

The Cruise Control is an big orange knob on a long lever that's right along the right side of the seat. It is connected to the pedals and they'll move when it does.

That's the orange knob that you said you were using to control forward speed instead of the pedal. That's one of the features on the B2910 that you don't see on the B7800. Others are arm rests, tilt wheel, extendable ends on the 3-point hitch arms.

I was just asking if you'd checked and double-checked that the "orange knob handle" (cruise control lever) was fully back in the "home" position.

To answer your last question -- I don't think the Cruise Control position matters since you have the safety jumped. But I also don't know if there's something internal to the transmission that prevents starting if you have your foot down on the pedal or cruise control is engaged -- other than the neutral switch.

Just pointing out that there's something going on if you get better response with the cruise handle than the pedal. Mine is equally smooth either way, but the pedal is much more convenient since it returns to the neutral position when you let off it and the cruise lever stays engaged until you pull it back or hit a brake.

 

[Jim Richardson]

That's the Brake Lock and the Tilt Wheel levers.

The Cruise Control is an big orange knob on a long lever that's right along the right side of the seat. It is connected to the pedals and they'll move when it does.

That's the orange knob that you said you were using to control forward speed instead of the pedal. That's one of the features on the B2910 that you don't see on the B7800. Others are arm rests, tilt wheel, extendable ends on the 3-point hitch arms.

I was just asking if you'd checked and double-checked that the "orange knob handle" (cruise control lever) was fully back in the "home" position.

To answer your last question -- I don't think the Cruise Control position matters since you have the safety jumped. But I also don't know if there's something internal to the transmission that prevents starting if you have your foot down on the pedal or cruise control is engaged -- other than the neutral switch.

Just pointing out that there's something going on if you get better response with the cruise handle than the pedal. Mine is equally smooth either way, but the pedal is much more convenient since it returns to the neutral position when you let off it and the cruise lever stays engaged until you pull it back or hit a brake.

Thank you. This is most helpful. I just adjusted my tilt wheel and it is in a notch. I never knew how to do that.

I think the big orange cruise handle gives better response as I get more leverage from it. Which likely means I should grease up the rocker pedal linkages when I reassemble.

I tested the safety switch and have continuity with the big orange cruise handle in its natural resting spot, and I lose continuity when I move it. I also tested every fuse in the fuse block, and then found near the starter, a 30A fuse which also tests as fine. I think it is time to test the starter, although there were no starting problems prior to this mowing. Thanks again.

 

[CH4Ohio]

Thank you. This is most helpful. I just adjusted my tilt wheel and it is in a notch. I never knew how to do that.

I think the big orange cruise handle gives better response as I get more leverage from it. Which likely means I should grease up the rocker pedal linkages when I reassemble.

I tested the safety switch and have continuity with the big orange cruise handle in its natural resting spot, and I lose continuity when I move it. I also tested every fuse in the fuse block, and then found near the starter, a 30A fuse which also tests as fine. I think it is time to test the starter, although there were no starting problems prior to this mowing. Thanks again.

I'm with you. I doubt the starter suddenly went bad. But that would be a good place to start working backward to find out where you have voltage and where you don't. I'd bet money that your starter is fine. The trick is to find out why there's no voltage getting to it when you turn the key.

 

[Jim Richardson]

I'd bet money that your starter is fine.

I just tested the starter. It is fine. The main terminal on the solenoid has 12V all the time.
https://photos.google.com/photo/AF1QipPPvoO1LcCry9pzOe78in7VezUo3CQHEjZFuW8U
The ignition spade has zero volts all the time, even when I have the key in the start position. A jumper cable from the battery to the ignition spade cranks the engine. That leaves me with good battery, good starter, but something in the safety switch circuit that keeps the ignition switch from sending current to the solenoid, even with all three safety switches jumped. It could be the ignition switch, but like everything else, there is no reason to think that would go bad all at once without any warning.

At this point, I am tempted to run some 16 ga wire from the battery, to a push switch I mount under the dash, and to the solenoid spade. Pushing the button will start the tractor. The tractor is 22 years old and needs to work, and both it and I are getting too old for this.

 

[CH4Ohio]

Are there 2 PTO safety switches? (Rear PTO and Mid PTO). Clutch switch. Neutral switch.

That would be 4.

My seat switch is jumped but not sure if it will keep it from starting or if that just kills the tractor when the PTO is on.

Just trying to think what else it could be.

 

[CH4Ohio]

I just tested the starter. It is fine. The main terminal on the solenoid has 12V all the time.
Google Photos
The ignition spade has zero volts all the time, even when I have the key in the start position. A jumper cable from the battery to the ignition spade cranks the engine. That leaves me with good battery, good starter, but something in the safety switch circuit that keeps the ignition switch from sending current to the solenoid, even with all three safety switches jumped. It could be the ignition switch, but like everything else, there is no reason to think that would go bad all at once without any warning.

At this point, I am tempted to run some 16 ga wire from the battery, to a push switch I mount under the dash, and to the solenoid spade. Pushing the button will start the tractor. The tractor is 22 years old and needs to work, and both it and I are getting too old for this.

Your photo didn't make it on this posting . . . What ignition spade are you talking about? On the starter switch itself?

What about the starter relay? It's part 50 on the diagram in your previous post. Any change in readings there when the key is turned to START??

 

[CH4Ohio]

Check your private messages. Sent you the troubleshooting routine from the Workshop Manual. Maybe something in there will help.

The seat switch doesn't seem to be in the circuit, but make sure it's closed anyway.

There's a "neutral range" safety switch but that's only supposed to affect certain B2710 models. Shouldn't be an issue here, but shift range selector to N while testing anyway. (Can't hurt)

Good luck.