Kubota L4600DT starting issue

[jshwhite]

Ditto on hating intermittent electrical issues. I've started having almost the exact same issue with the L4740. Reading through this has me thinking to check my seat safety switch, as at one point I jumpered it so maybe my connections are getting loose.

Let us know what you figure out...

 

[bearthebruce]

Not a Kubota, but our Massey was new to us - not new - in 2017. We started using it for work in making trails and mowing. It started dying as has been described in this thread.

As I am an EE, I figured it was a safety switch and it seemed it was the seat safety. As long as my fat derrier was in the seat, all was fine but put a light weight behind the wheel and nothing but troubles.

Played with the knob that is supposed to compensate for the fat old boy versus the young kid.. nope..

Lifted the seat and looked at the mechanism. The bar in the frame that is supposed to hold the switch is broken off the frame and depending on where the bar shifted in operation, the switch made contact or didn't. On further inspection, we found the bar rusted, the welds failed and the switch housing broken.

Some big boy needed to get up high for something and decided the tractor seat was a good stair step! The foot in the center of the seat likely broke everything.

Its all been repaired and we have had no further issues.

Yep - being a short portley, when I need to look out the front of the tractor, I often cause the engine to stall. Also happens on some of the 20 degree slopes depending on what I am doing.

I built a seat defeat jumper I can just plug into the connector. I need to find it again... seems to have been misplaced.

Hope you trace it down Tammy.

 

[rScotty]

Fuel solenoid valve.

 

[tammyemond]

okay, ask him how he does the following sequence.
1- making sure the shuttle shift lever is in neutral. When he cranks then does it start? if so shuttle shift safety switch is working at least partially.
2- move the shuttle shift to forward and try to crank. Engine should not crank.
3- move the shuttle shift in reverse and try to crank. Engine should not crank.
4- you said he is a smaller guy, kind of like me. Does he need to move forward to shift the gear? if so may be seat switch kills the engine. When I use the loader and have to move closer to the steering wheel or look up the hood to see the edge of the bucket sometime my rig wants to shut off.
5- Simply take a rubber band and connect it to the the end of set switch plastic arm and tie it off the something there to simulate it fully depressed. Basically, overriding the seat switch and force it to close and see if that make any difference. I am not at all proponent of messing with the safeties , here what we're doing is just to diagnose a problem.

If you had a major issue tractor would not continue running. it must be something silly such as an lose eclectically fitting (male and female connector not sitting in) or not adjusted right. Let us know Tammy.

It died as soon as he took it out of neutral. Seat switch is tied down, it has been for years because he does a lot of backing while bush hogging and he was tired of it trying to shut down. He doesn't have to move forward to shift between 1st, 2nd, 3rd, and 4th. It started and ran fine again today. He didn't see any apparent critter damage to the wiring. We still haven't found a PTO safety switch.

 

[tammyemond]

Tammy if you have a harbor freight near by you can get a cheap
multi meter. Or get one from the auto parts store

willy

The one we have came from harbor freight, never was that great. We'll have to spring for a decent one when we can. We may be able to borrow one for the time being.

 

[tammyemond]

Not a Kubota, but our Massey was new to us - not new - in 2017. We started using it for work in making trails and mowing. It started dying as has been described in this thread.

As I am an EE, I figured it was a safety switch and it seemed it was the seat safety. As long as my fat derrier was in the seat, all was fine but put a light weight behind the wheel and nothing but troubles.

Played with the knob that is supposed to compensate for the fat old boy versus the young kid.. nope..

Lifted the seat and looked at the mechanism. The bar in the frame that is supposed to hold the switch is broken off the frame and depending on where the bar shifted in operation, the switch made contact or didn't. On further inspection, we found the bar rusted, the welds failed and the switch housing broken.

Some big boy needed to get up high for something and decided the tractor seat was a good stair step! The foot in the center of the seat likely broke everything.

Its all been repaired and we have had no further issues.

Yep - being a short portley, when I need to look out the front of the tractor, I often cause the engine to stall. Also happens on some of the 20 degree slopes depending on what I am doing.

I built a seat defeat jumper I can just plug into the connector. I need to find it again... seems to have been misplaced.

Hope you trace it down Tammy.

Seat switch is tied down, maybe we can make a jumper for it instead and see if that helps the next time it acts up. It's just so random. It's gone from not starting at all to starting but dying as soon as it is taken out of neutral. It's all intermittent though, there isn't any constants.

 

[JC-jetro]

Seat switch is tied down, maybe we can make a jumper for it instead and see if that helps the next time it acts up. It's just so random. It's gone from not starting at all to starting but dying as soon as it is taken out of neutral. It's all intermittent though, there isn't any constants.

Seat switch might be held down with rubber band or a piece of string but that is not full proof. You need to verify change of state from being tied or not tied. safety switched normally are in closed state, what that means the contacts on the switch are made with a help of some sort of spring and metal that acts as spring. So basically all closed switches make the circuit complete and if one of them opens up breaks the continuity. Now I am a ME and not EE but know enough electrical stuff to be " real dangerous" you can make a very simple test light combining a battery, wires, a light bulb and two alligator clips. Clips touch and the light comes on. With that you can check any single or double pole switches. What you want to be sure light illuminates with the switch is on and light goes off when the switch is off.

 

[JC-jetro]

The one we have came from harbor freight, never was that great. We'll have to spring for a decent one when we can. We may be able to borrow one for the time being.

I have several meters form high$$$ fluke to very affordable quality Sperry that is actually clamp on amp meter to sevarl freebie cheap HF ones. I have really never had any problem with HF as I mainly check 12 volt and continuity with them In every car we own, every tractor and 4 wheeler I have a HF meter and if I should run over it and bust it then I would not lose sleep over. Below is the link for a sensible meter that I have had for more 15 years and never failed me.

Sperry 400 Amp Digital Clamp Meter DSA500AR - The Home Depot

The DSA500A Sperry Instruments Snap-Around Clamp Meter is a 5-function, 9-range auto-ranging unit engineered to measure AC Current (40-400 Amp), AC/DC Voltage (400/600-Volt), Resistance (400/4000) and

www.homedepot.com

 

[JC-jetro]

Fuel solenoid valve.

Could not rule it out. Some of the circuit also are switched with relays. Any of them could be culprit. The only diagnosis is done by process of elimination that's easier said than done.

 

[tammyemond]

Seat switch might be held down with rubber band or a piece of string but that is not full proof. You need to verify change of state from being tied or not tied. safety switched normally are in closed state, what that means the contacts on the switch are made with a help of some sort of spring and metal that acts as spring. So basically all closed switches make the circuit complete and if one of them opens up breaks the continuity. Now I am a ME and not EE but know enough electrical stuff to be " real dangerous" you can make a very simple test light combining a battery, wires, a light bulb and two alligator clips. Clips touch and the light comes on. With that you can check any single or double pole switches. What you want to be sure light illuminates with the switch is on and light goes off when the switch is off.

I'll have to see if I can make a test light or borrow a meter from one of our neighbors. The way you explain it, it seems simple enough. We definitely need to test the seat switch to make sure it is still making a connection. Thank you.