L3430 won't stay running

spock · May 30, 2011

I have an 03 L3430 HST with about 700 hours on it. I moved it from the garage to the field no problem. Removed FIL and backing out to remove the box blade and it will not stay running.
has fuel (full) no other problems in the 700 hours I've owned it.

Did a quick search and it seems it could be the fuel solenoid I am going out to check.

Any other sugestions? This is the first problem with this tractor, not sure where to look.

Thanks

Spock

kuboman · May 30, 2011

spock said:
I have an 03 L3430 HST with about 700 hours on it. I moved it from the garage to the field no problem. Removed FIL and backing out to remove the box blade and it will not stay running.
has fuel (full) no other problems in the 700 hours I've owned it.

Did a quick search and it seems it could be the fuel solenoid I am going out to check.

Any other sugestions? This is the first problem with this tractor, not sure where to look.

Thanks

Spock

You have to be more specific about 'not running'.
I would check all the safety lock out switches.

spock · May 30, 2011

Won't run is it starts fine the dies soon after it starts.
It seems the cut-off solenoid disengages.

Checked the cut-off sol. it is OK (Jumbered it out to get her back to the garage)

Tested the relay the activates the cut-off sol. it is OK (connected straight to battery and checked continuity with DMM)

The wire that feeds the relay is intermittent voltage is dropping out.

Not sure what else is in that circuit, no electrical diagram.

Thanks

Spock

jimbo64 · May 30, 2011

change the fuel filter-sounds like its starving

spock · May 31, 2011

Fuel filter is fine one of the first things I checked.

It is electrical either a wiring issue/ loose connection or what ever controls the relay for the shut off solenoid. I can hear the solenoid disengaging.

Trying to find a wiring diagram to trace it out.

And we have hay down.

Thanks

Spock

Grandad4 · May 31, 2011

If fuel filter is OK, then it sure sounds like one of the safety switches is giving you fits. The solenoid itself is most likely not the problem, but all those interlock switches can drive you batty. Do you have owner's manual? That should list all the safety circuits to check. Hope you find the problem quickly!

crazyal · May 31, 2011

Does it idle fine but as soon as you go to move die? What about if it's idling and you engage the PTO? Does it stay running or does it die? If it stays running then how about if you get off the seat, does it die? You can always start to disconnect (or jumper) each interlock until you find the one not working. A better way would be to go to the dealer (unless someone here has it) and get a copy of the wiring diagram. With it and a multi meter you should easily be able to track down where the power is getting disconnected. You may also want to try and do a detailed look around to see if a stick or something caught a wire.

rustedduck · May 31, 2011

You might also check to make sure you fuel cap is correctly
seated.

Milton Burro · May 31, 2011

My manual dies at times when I start to let the clutch out. I'm thinking seat switch, I'll install a temporary jumper to see if it removes the problem.

David_Kb7uns · May 31, 2011

If after the tractor dies you hear a click then that means the circuit to shutoff the tractor is releasing the solenoid after the timer relay goes through its cycle. Many smaller KUBOTA tractors have an external solenoid the pulls the stop lever for stopping the engine, some have solenoids that are bolted to the engine that have two circuits where one coil is sometimes energized to run and another coil is energized to stop. It is sounding like one of the seat, PTO or other switches is momentarily loosing contact and thus triggering the shutoff timer relay and the relay turns on until the engine comes to a stop and then releases.

David Kb7uns

slowzuki · May 31, 2011

Usually the seat switch or pto switch. There are several safety switches on the machine, a similar thread was recently posted and it was a loose connection on the oil pressure switch on the engine I believe?

Nope it was the tach sensor:
http://www.tractorbynet.com/forums/...01216-grand-l5030-starts-idles-perfectly.html

Without the tach the safety logic couldn't tell the engine was running and closed the fuel shutoff.

funkster995 · May 31, 2011

the L3430 has a 30amp slow blow fuse that supplies 12 v to the key stop solenoid relay. If you have 12v to relay, fuse is not it. Relay gets turned on or off by: OPC timer (operator presence control timer, looks like a relay under dash), seat switch, mid pto switch, rear pto switch, or shuttle switch. If any of those switches or timer is bad, relay will not turn on. Hope this helps.:confused2:

spock · May 31, 2011

My guess is the OPC timer, if that is moved the relay cuts out.
That is the part I ordered at the dealer anyway. Should be here Thursday.

Hope that is the problem.

In the mean time I have by-passed the relay, raked hay for two hours with no issues.

Thanks for all the advice.

Spock

David_Kb7uns · Jun 1, 2011

slowzuki said:
Nope it was the tach sensor:
http://www.tractorbynet.com/forums/...01216-grand-l5030-starts-idles-perfectly.html

Without the tach the safety logic couldn't tell the engine was running and closed the fuel shutoff.

The tach sensor only goes to the Intellipanel it has no connection to the engine cutoff system.

David Kb7uns

spock · Jun 3, 2011

Update

It was indeed the OPC timer. Picked it up at the dealers yesterday and problem solved.
$76.00 with 2nd day air delivery, not too bad since this the only money spent on my tractor other than normal maintenance with almost 700 hours on it.

Actually the hard part was putting the "dash" cover back on that was a real pain.

Thanks for all the help

Spock

daveinnh · Jan 7, 2013

I understand that this is an older thread - but we have a L4310 with a similar problem.

Does an L4310 even have an OPC timer? If so who does it interface with the fuel shot-off solenoid?

How do you test an OPC Timer?

Photos / diagrams appreciated...

nsgoldberg · Jun 26, 2021

Realize this is an old thread, but just troubleshooted my OPC timer and figured I'd share this.

The OPC is behind the instrument cluster. A 10mm bolt holds it in place. It's #3 in the photo.

Here is the replacement for my L2800:

Kubota #TD060-30500 TIMER OPC SWITCH

TIMER OPC SWITCH

www.messicks.com

Hemmjo · Aug 5, 2025

spock said:
My guess is the OPC timer, if that is moved the relay cuts out.
That is the part I ordered at the dealer anyway. Should be here Thursday.

Hope that is the problem.

In the mean time I have by-passed the relay, raked hay for two hours with no issues.

Thanks for all the advice.

Spock

I know this is an old thread, but, HOW did you bypass the OPC switch? does anyone know how to test the OPC switch? They are $130 now, hate to buy one and have that not be the problem.

I found one thread here with a description of how to test it, but there is either something wrong with the description, OR perhaps I don't understand the explanation.

L3130 OPC Timer Relay

I believe the OPC is the source of my random engine shutdown. There are four leads red, black, yellow and red/white. Can anyone shed light on which are the input wires and which are the output?

www.tractorbynet.com

Thanks,

John