L48 start problems

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
Good afternoon I have an L 48 that I am having problems with. I cannot get it to crank and start. I have jumper it the PTO switch no help. I have jumper did the clutch pedal safety switch no help I replace the ignition switch no help.Any help would be greatly appreciated. I have called local tractor mechanics and of course they’re too busy. Cows need fed I need to get it going ASAP.
 

Motion

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Equipment
Kubota MX5100HST/FEL
Aug 17, 2020
540
302
63
Mandeville Louisiana
When's the last time it ran? Ensure that the tractor is in neutral and the brakes engaged, run a jumper wire from the positive on the battery to the start terminal of the solenoid if it turns over, then the battery, battery cables/connections, solenoid and starter are good. If you have an electric fuel cut off, jack it open and it should fire off. If it runs check your wiring diagram to determine the break/bad connection between the battery/fuse/switch/safeties, etc. Be reminded that grounds are critical to the electrical system
 

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
When's the last time it ran? Ensure that the tractor is in neutral and the brakes engaged, run a jumper wire from the positive on the battery to the start terminal of the solenoid if it turns over, then the battery, battery cables/connections, solenoid and starter are good. If you have an electric fuel cut off, jack it open and it should fire off. If it runs check your wiring diagram to determine the break/bad connection between the battery/fuse/switch/safeties, etc. Be reminded that grounds are critical to the electrical system
I got it started for a few minutes yesterday. It acts like one of the safety switches is acting up. I have power to everything it seems except to the cranking side of the starter.
 

Motion

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Lifetime Member

Equipment
Kubota MX5100HST/FEL
Aug 17, 2020
540
302
63
Mandeville Louisiana
The good news is that it's capable of running. You say you got it "running for a few minutes" did you turn it off or did it just die? If it just died it may be your fuel cut off solenoid, check if it has two or three wires, if two disconnect and apply 12 volts to test, if three there's start and run contacts, you can bench test to confirm if it's good, refer to your WSM for how to test. You could try disconnecting the start wire off of the solenoid and connect you volt meter to it to see if you're getting a full 12 volts to it when turning the key to start.
 

Henro

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Equipment
B2910, BX2200, KX41-2V mini Ex., Beer fridge
May 24, 2019
5,803
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North of Pittsburgh PA
I got it started for a few minutes yesterday. It acts like one of the safety switches is acting up. I have power to everything it seems except to the cranking side of the starter.
It almost sounds like you might have two issues with the root cause being something related to the safety interlock circuit.

You really need to get an electrical diagram to see how things are interconnected. Not sure if you can find a free workshop manual online or not.

The fact that you can get the starter to turn the engine over when you use a jumper indicates that there is an issue with the safety interlock circuit that activates the starter.

Somehow the safety interlock circuit could also be connected to the fuel cut off circuit, but I have no idea about your tractor.

I think getting a workshop manual would be a wise next move. Perhaps someone that is familiar with your specific tractor can participate and give some guidance. Hope so!
 

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
It almost sounds like you might have two issues with the root cause being something related to the safety interlock circuit.

You really need to get an electrical diagram to see how things are interconnected. Not sure if you can find a free workshop manual online or not.

The fact that you can get the starter to turn the engine over when you use a jumper indicates that there is an issue with the safety interlock circuit that activates the starter.

Somehow the safety interlock circuit could also be connected to the fuel cut off circuit, but I have no idea about your tractor.

I think getting a workshop manual would be a wise next move. Perhaps someone that is familiar with your specific tractor can participate and give some guidance. Hope so!
I am not able to get the starter to turn over. I have jumpered the clutch, pro, and the seat with no luck
The good news is that it's capable of running. You say you got it "running for a few minutes" did you turn it off or did it just die? If it just died it may be your fuel cut off solenoid, check if it has two or three wires, if two disconnect and apply 12 volts to test, if three there's start and run contacts, you can bench test to confirm if it's good, refer to your WSM for how to test. You could try disconnecting the start wire off of the solenoid and connect you volt meter to it to see if you're getting a full 12 volts to it when turning the key to start.
It ran until I turned it off. After I turned it off and try to start it again no go.
 

Motion

Well-known member
Lifetime Member

Equipment
Kubota MX5100HST/FEL
Aug 17, 2020
540
302
63
Mandeville Louisiana
Are you sure that the battery connections are clean and tight? Are you getting a full 12 volts to the solenoid start terminal? If you have a woven ground strap connect one of your jumper cables (not wire) from the negative post to a good/clean engine ground. Also did you try jumping straight to the positive terminal of the starter or at least across the two large terminals of the solenoid.
 

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
Are you sure that the battery connections are clean and tight? Are you getting a full 12 volts to the solenoid start terminal? If you have a woven ground strap connect one of your jumper cables (not wire) from the negative post to a good/clean engine ground. Also did you try jumping straight to the positive terminal of the starter or at least across the two large terminals of the solenoid.
No I haven’t checked the solenoid yet. Been concentrating on the safety switches. Is there one on the speed selector?
 

Motion

Well-known member
Lifetime Member

Equipment
Kubota MX5100HST/FEL
Aug 17, 2020
540
302
63
Mandeville Louisiana
You really need a wiring diagram. I don't recommend jumping out safeties but if I was in dire need, I'd do what's ever necessary to take care of business then fix the problem.
 

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
You really need a wiring diagram. I don't recommend jumping out safeties but if I was in dire need, I'd do what's ever necessary to take care of business then fix the problem.
I agree with fixing the problem right. I was hoping to find that one of the safety switches is bad. Is there a starter relay or something similar?
 

rbargeron

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Equipment
L5450, L48, L3250, L345 never enough attachments
Jul 6, 2015
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western ma
No I haven’t checked the solenoid yet. Been concentrating on the safety switches. Is there one on the speed selector?
The clutch pedal switch on my L48 is inside the dash left side- operated by the clutch pedal rod. And there's a switch on the L-M-H linkage under the right floorboard.
 

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
The clutch pedal switch on my L48 is inside the dash left side- operated by the clutch pedal rod. And there's a switch on the L-M-H linkage under the right floorboard.
I found the one on the pedal, I haven’t located the one on the linkage yet
 

rbargeron

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L5450, L48, L3250, L345 never enough attachments
Jul 6, 2015
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western ma
On mine the wiring isn't "original" on the linkage switch - maybe it acted up?
 

FRS

New member

Equipment
L48
May 24, 2021
9
0
1
Shelton, Wa
Does anyone know which relay is the start relay? There are 3 in the upper right and three on the middle left under the dash.
 

rbargeron

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Equipment
L5450, L48, L3250, L345 never enough attachments
Jul 6, 2015
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western ma
The ones in the upper right are the glow plug controller etc.
Starter relay is 3rd from the right in the group on the left side.
 

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Henro

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Equipment
B2910, BX2200, KX41-2V mini Ex., Beer fridge
May 24, 2019
5,803
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North of Pittsburgh PA
I am not able to get the starter to turn over. I have jumpered the clutch, pro, and the seat with no luck

It ran until I turned it off. After I turned it off and try to start it again no go.
Sorry, misunderstood.

So it sounds like the typical safety circuit issue.

It is possible (but can be dangerous) to turn the engine over using a jumper at the starter to apply voltage directly to the solenoid terminal. Doing this eliminates the possibility of a starter issue if the engine turns over, but is not recommended for safety Reasons. IF you would do this, best to have the tractor in neutral and sombody in the seat holding the brakes on.

It is Something that might be done if there is an urgent need to use the tractor.

Otherwise, you will likely solve the problem. Just takes time And effort...