excavator

[bguillory]

shot in the dark, would anyone have a digital copy of the wiring schematic for a KH-18L excavator. Borrowed this old machine from my brother, who bought it used. Need the schematic to possibly track down a starting issue. Can jump the starter and glow plugs and machine will start and operate. Replaced ignition switch thinking it was problem but no luck. Need to start tracing wires to see where issue is and a schematic would be so helpful. Thanks in advance if someone can help me.

 

[Henro]

shot in the dark, would anyone have a digital copy of the wiring schematic for a KH-18L excavator. Borrowed this old machine from my brother, who bought it used. Need the schematic to possibly track down a starting issue. Can jump the starter and glow plugs and machine will start and operate. Replaced ignition switch thinking it was problem but no luck. Need to start tracing wires to see where issue is and a schematic would be so helpful. Thanks in advance if someone can help me.

It is almost certainly a safety interlock issue, or possibly a problem with contacts in the safety circuit developing resistance with age, like is common on some tractors and solved by using an interposing relay between the starter solenoid and the safety circuit.

Take the wire off the starter solenoid that activates it through the key circuit, and measure voltage when you turn the key to the start circuit. If you have full voltage, then put the wire back on the starter solenoid terminal, and measure voltage again when you try to start. If the voltage is now very low, you will have a good idea that the problem is resistance in the safety circuit.

The easiest solution in this case is to use an interposing relay. The relay coil is energized by the safety circuit, and the relay feels ample voltage, because its current draw is much less than the starter solenoid requires. Contacts of the new relay are used to put 12 volts onto the starter solenoid terminal.

If you have zero voltage when checking the wire you removed from the starter solenoid, then you have a more serious issue, like a failed safety switch or a broken wire.

Just a couple hints...hopefully helpful

 

[North Idaho Wolfman]

I don't have The WSM for that model, but other similar models show it to be a direct connection from switch to starter, Via a fuse link down by the starter.
If your not getting power to the ignition switch look again at the fuse link down by the starter.

 

[bguillory]

Thanks Henro and wolfman for the input. Definately going to check for that fuse link, but the glow coils don't get voltage either. Will try trace out safety circuits, this old thing in pretty poor shape. Few switches on the controls dashboard are broken, and I don't even know what they are for. All stickers, etc. are gone or faded out. Thanks again guys, perhaps a copy of the similar schematics would help if someone has one.

 

[Henro]

I don't have The SM for that model, but other similar models show it to be a direct connection from switch to starter, Via a fuse link down by the starter.
If your not getting power to the ignition switch look again at the fuse link down by the starter.

Just a quick question.

That seems so strange to me that there would be no safety interlocks, and a direct connection directly to the starter from the switch.

Wolfman, is this normal on excavators? Just seems dangerous...

I just bought a used mini ex and will have to see how it is wired up. Hopefully the documentation I have on hand will include an electrical diagram.

 

[North Idaho Wolfman]

Just a quick question.

That seems so strange to me that there would be no safety interlocks, and a direct connection directly to the starter from the switch.

Wolfman, is this normal on excavators? Just seems dangerous...

Yes on older EX's very normal, and yes they were dangerous!
You could start them and be holding the sticks so it would start and swing/ move at the same time.

Newer units have several styles of interlocks to help keep things safer.

 

[Henro]

Yes on older EX's very normal, and yes they were dangerous!
You could start them and be holding the sticks so it would start and swing/ move at the same time.

Newer units have several styles of interlocks to help keep things safer.

Thanks Wolfman!

 

[North Idaho Wolfman]

Thanks Henro and wolfman for the input. Definately going to check for that fuse link, but the glow coils don't get voltage either. Will try trace out safety circuits, this old thing in pretty poor shape. Few switches on the controls dashboard are broken, and I don't even know what they are for. All stickers, etc. are gone or faded out. Thanks again guys, perhaps a copy of the similar schematics would help if someone has one.

Here is the link for the manual for the larger units, they will be very similar.

http://kubotabooks.com/AutoIndex/index.php?dir=Excavators/&file=Kh36-41-51-61-66-91-101-151-Workshop%20manual..pdf

 

[North Idaho Wolfman]

Thanks Wolfman!

Have you gotten to work with yours?
That is my next purchase is I can swing it!

 

[Henro]

Have you gotten to work with yours?
That is my next purchase is I can swing it!

No, thin blood I guess.

Waiting until spring and warmer weather, unless a reason comes up.

Age breeds patience I suppose.

 

[Henro]

No, thin blood I guess.

Waiting until spring and warmer weather, unless a reason comes up.

Age breeds patience I suppose.

Yes on older EX's very normal, and yes they were dangerous!
You could start them and be holding the sticks so it would start and swing/ move at the same time.

Newer units have several styles of interlocks to help keep things safer.

I was going to post this question separately but I thought it might be of some use to the OP, so I’ll post it here.

I looked at the electrical drawing for my KX41-2V. In my case the battery voltage comes off the starter and through an in-line fuse as described by Wolfman in his previous post.

The voltage then goes onto the switch and comes back to the starter solenoid directly.

My question relates to what is on the other side of the starter solenoid. In the case of my BX 2200 tractor, there is the fuel solenoid which completes the circuit that energizes the starter solenoid. In the case of the KX, I’m not familiar with what the symbol shown in the following screenshot is.

Can somebody tell me what this symbol represents?

 

[Motion]

When troubleshooting electrical problems, especially on older machines, ALL ground wires and connection points are very important. Just my .02

 

[North Idaho Wolfman]

I was going to post this question separately but I thought it might be of some use to the OP, so I’ll post it here.

I looked at the electrical drawing for my KX41-2V. In my case the battery voltage comes off the starter and through an in-line fuse as described by Wolfman in his previous post.

The voltage then goes onto the switch and comes back to the starter solenoid directly.

My question relates to what is on the other side of the starter solenoid. In the case of my BX 2200 tractor, there is the fuel solenoid which completes the circuit that energizes the starter solenoid. In the case of the KX, I’m not familiar with what the symbol shown in the following screenshot is.

Can somebody tell me what this symbol represents?

View attachment 53136

That would be the extra wire that comes off the starter for the stop / run / fuel solenoid.
It's just an odd way to show it's and unused terminal.
And it's actually the other way around, the starter solenoid supplies voltage that pulls the fuel solenoid open, then the second wire to the fuel solenoid gives it the hold voltage.

 

[Henro]

That would be the extra wire that comes off the starter for the stop / run / fuel solenoid.
It's just an odd way to show it's and unused terminal.
And it's actually the other way around, the starter solenoid supplies voltage that pulls the fuel solenoid open, then the second wire to the fuel solenoid gives it the hold voltage.

So we may have the source of the OP's issue, but that does not make sense as his excavator runs after he jumps it at the starter...so his may be entirely different.

My BX would not run or even try to start with the fuel solenoid unplugged. With it plugged in it would start and immediately stop when the key was released to the on position. The hold coil was apparently bad. A new solenoid fixed the issue.

But the OP's engine will run after it is started, by the procedure he stated. This is puzzling.

So I guess we get back to what the actual wiring of the OP's excavator is...which we do not know.

By the way, I wish Kubota actually showed a diagram of what the wiring is INSIDE the starter...

 

[Henro]

That would be the extra wire that comes off the starter for the stop / run / fuel solenoid.
It's just an odd way to show it's and unused terminal.
And it's actually the other way around, the starter solenoid supplies voltage that pulls the fuel solenoid open, then the second wire to the fuel solenoid gives it the hold voltage.

I know how the circuit on my BX works, the pull in coil is activated by the current that flows through the starter solenoid when that same current activates the solenoid, which causes the starter to turn. The hold coil is energized when the key is in the on position (And also in the start position if I remember right).

But the circuit on the KX41-2 that I pictured above uses a timer to activate the “stop” solenoid. I took that to indicate the KX activates the stop solenoid for a time, to cut off fuel, when the key is turned to off, but have not followed that part of the diagram yet, as l got sidetracked by that symbol I asked about.

Having a “stop” solenoid that is activated by a timer could imply that a hold coil is not needed, as the fuel path might likely be open until the solenoid was activated.

At this point I am not sure my question is contributing any help to the OP...

BUT if the OP’s circuit happened to be the same as the one I pictured, by starting his excavator, by shorting between the terminals on the starter, he would have verified that device I questioned was not his issue.

 

[North Idaho Wolfman]

Henro,
His issue is not a run issue, and it's not a fuel solenoid issue.
His issue is no power either to the switch or from the switch in order to power the solenoid or the glow plugs.

 

[whitetiger]

Henro,
His issue is not a run issue, and it's not a fuel solenoid issue.
His issue is no power either to the switch or from the switch in order to power the solenoid or the glow plugs.

Will this help any?

 

[bguillory]

Here is the link for the manual for the larger units, they will be very similar.

http://kubotabooks.com/AutoIndex/index.php?dir=Excavators/&file=Kh36-41-51-61-66-91-101-151-Workshop%20manual..pdf

Thanks wolfman! I think this wiring diagram is close enough to what I have, should help a bunch!

 

[Henro]

Will this help any?

I think so.

It is obvious from this diagram that the power to the starter comes directly from start switch terminal 50 to the starter via a connector. So either the switch is bad, or the connector is bad, or a wire is broken...

 

[North Idaho Wolfman]

Thanks wolfman! I think this wiring diagram is close enough to what I have, should help a bunch!

Did you see the post by whitetiger, that is yours exactly.