L3700SU

[HillMowpow]

My tractor won't start.
Checked all that follow:
Starter relay. Clicks when electrified
Glow plug, clicks when electrified.
Seat switch works fine.
Checked plunger on hydrostatic pedal..disengages and engages fine so neutral.
Checked clutch side.
Checked PTO
Checked all fuses in box and by battery.
Battery reads 12.5 amp when key turned drops to 11.9

Maybe??? Key switch ignition?

Any schematic electric diagrams on this tractor would be helpful. Or if you know how much powered should be going where...this too would be helpful.

Is there a way to check the switches at plunger with multimeter. If so how, and specifics on ohms please.

Can the engine go into gag mode so it doesn't get ruined other than fuses and relays?

Previously had problems with fuel lines and hand to buy new fuel filter and new diesel.

Maybe fuel shut off? Is this the fuel pump or something totally different?

 

[Hkb82]

I think your battery should be still reading over 12v with key turned without turning over the motor. How about the starter itself. Have you verified it’s working? Could pop it off if to to hard and put 12v to it for test. Those are the first two things that come to mind. I don’t think if it were a safety switch you would get the clicking like it’s wanting to start. Just my thoughts though.

 

[North Idaho Wolfman]

My tractor won't start.

I'm having several issues with your statements:

Starter relay. Clicks when electrified.

Just because it "clicks" doesn't mean it works!

Glow plug, clicks when electrified.

Glow plugs don't "Click"

Seat switch works fine.

How do you know?

Checked plunger on hydrostatic pedal..disengages and engages fine so neutral.

What are you talking about?

Can the engine go into gag mode so it doesn't get ruined other than fuses and relays?

Again, what are you talking about?

Previously had problems with fuel lines and hand to buy new fuel filter and new diesel.
Maybe fuel shut off? Is this the fuel pump or something totally different?

Does it crank and not fire?

The wiring diagram is located in the WSM.

 

[Roadworthy]

Check the battery voltage when you try to engage the starter. It should be above ten volts. If it is then clean and tighten battery cables. Follow ground cable to frame, clean and tighten there, too. From there we can start troubleshooting.

 

[HillMowpow]

Check the battery voltage when you try to engage the starter. It should be above ten volts. If it is then clean and tighten battery cables. Follow ground cable to frame, clean and tighten there, too. From there we can start troubleshooting.

Battery isn't the problem. It does not drop when key is turned. It's at 11.9 volts with multimeter check.
Solenoid is not problem nor the starter, tried it directly to battery and it engages and goes.
We replaced the Unit flasher relay and the glow plug relay under bonnet.
The opc timer that is also located under the bonnet ( the one with a tail plug in harness) we are wondering how to test? We don't know if this acts like relay or switch? We don't know if certain pins need to be energized in order to close the gap and create a flow of energy or if it has any ohm reading at all, bc as of now it does not. But again it's not energized.

 

[HillMowpow]

I'm having several issues with your statements:


Just because it "clicks" doesn't mean it works!


Glow plugs don't "Click"


How do you know?


What are you talking about?


Again, what are you talking about?


Does it crank and not fire?

The wiring diagram is located in the WSM.

What is WSM?

 

[HillMowpow]

What is WSM?

What is WSM?

Correct glow plugs don't click but the relay for it does when energized on the one side of pins.

 

[HillMowpow]

Tractor will not make any sounds whatsoever. No click. But ... We bypassed key and directly energized starter and solenoid and the wheel pops forward and spins. So not starter motor.

What should be the reading on each of these relays just under the bonnet on then L bracket? Or does anyone know?

 

[HillMowpow]

Tractor will not make any sounds whatsoever. No click. But ... We bypassed key and directly energized starter and solenoid and the wheel pops forward and spins. So not starter motor.

What should be the reading on each of these relays just under the bonnet on then L bracket? Or does anyone know?

I need a list of all to check:

Seat switch is bypassed wired with wire nut cap.

Glow plug relay closes the gap when energized. (How many glow plugs are there...how to check them properly)

Hydrostatic or speed pedal switch works proper and nothing is wedged to keep it in a forward nor backward position.

The clutch pedal plunger works properly and moves freely when depressed or released.

 

[HillMowpow]

My tractor won't start.
Checked all that follow:
Starter relay. Clicks when electrified
Glow plug, clicks when electrified.
Seat switch works fine.
Checked plunger on hydrostatic pedal..disengages and engages fine so neutral.
Checked clutch side.
Checked PTO
Checked all fuses in box and by battery.
Battery reads 12.5 amp when key turned drops to 11.9

Maybe??? Key switch ignition?

Any schematic electric diagrams on this tractor would be helpful. Or if you know how much powered should be going where...this too would be helpful.

Is there a way to check the switches at plunger with multimeter. If so how, and specifics on ohms please.

Can the engine go into gag mode so it doesn't get ruined other than fuses and relays?

Previously had problems with fuel lines and hand to buy new fuel filter and new diesel.

Maybe fuel shut off? Is this the fuel pump or something totally different?

On the glow plug relay wire harness when key is off it reads on the big terminals of 12.55 volts. When key is engaged on big terminals either glow or start it drops to 11.81 volts.

The two smaller openings on glow plug wire harness when key to the left (glow) or right (start) reads 0.41 ohms. When key off on lower openings of the harness we get 0 volts.

It seems this is backwards and won't make the glow plug relay work properly.
The upper big lugs we got zero ohms until we energized the lower little two lugs. When we did an ohms test the lower two we got 81 ohms while not energized.

 

[HillMowpow]

On the glow plug relay wire harness when key is off it reads on the big terminals of 12.55 volts. When key is engaged on big terminals either glow or start it drops to 11.81 volts.

The two smaller openings on glow plug wire harness when key to the left (glow) or right (start) reads 0.41 ohms. When key off on lower openings of the harness we get 0 volts.

It seems this is backwards and won't make the glow plug relay work properly.
Plug:
The upper big lugs we got zero ohms until we energized the lower little two lugs. When we did an ohms test the lower two we got 81 ohms while not energized. That's the coil and must be energized in order to close the gap to create a flow of energy.

It seems like something is shorting out or is pulling energy.

The OPC timer thing..the one with harness out the bottom... relay, switch ???)doesn't have any continuity when checked on any of the pins. Should it? Does it have to be energized?

Harness:
On the OPC Timer male harness connector between red w/black stripe and black with blue stripe with in key off or on it read zero volts.
Now the solid black wire and the black w/blue stripe wire when tested with key off or on read zero volts.

On top the the two black with blue striped wires (the top right and lower right) key on or off read zero volts.

The only voltage found is with the upper left (red w/black stripe)
Bottom left solid black wire. Key off reads zero volts. Key start it dropped to 11.43 volts. When returned to run position the voltage jumped up to 12.43 volts.

Now when turned key for glow plug left read same 11.43 volts.
But when put back on run it read zero volts.

 

[HillMowpow]

Because there is no work shop manual for L3700SU already looked on their website.

 

[Hkb82]

What keeps bringing ya to the glow plugs? I wouldn’t think a glow plug is what’s stopping it from starting. Obviously maybe in cold weather but now? Could try pulling fuse or disconnecting glow plugs altogether then try starting to see if they are drawing to much or changes anything. No clue if this is a good idea but it’s an idea. Not really a reading but more process of elimination.
Given the amount of testing you’ve done I’m gonna assume you have checked and cleaned all grounds and connections/harnesses for proper connection. Might not be a bad idea to dbl check your seat safety bypass. Pto safety switch might be another place to look around. Neutral safety switch maybe.

 

[old and tired]

Because there is no work shop manual for L3700SU already looked on their website.

Look for a manual for either an L3400 or L3800; your model was created when they changed from the L3400 model to the L3800.

I always assume it was to use up extra parts that were left over from the L3400 model; since new production was geared to only making L3800 parts. No facts, just a guess.

I've confirmed with one guy that had an L3700, that he did not have a suspension (springs) seat base. Just a hard frame. Does yours have a suspension seat?

 

[North Idaho Wolfman]

WSM = Work shop Manual (aka Service manual)

Kubota #9Y011-13194 L2800, L3400, L3700SU Shop Manual

Kubota #9Y011-13194 L2800, L3400, L3700SU Shop Manual

0.0

www.messicks.com

 

[HillMowpow]

Look for a manual for either an L3400 or L3800; your model was created when they changed from the L3400 model to the L3800.

I always assume it was to use up extra parts that were left over from the L3400 model; since new production was geared to only making L3800 parts. No facts, just a guess.

I've confirmed with one guy that had an L3700, that he did not have a suspension (springs) seat base. Just a hard frame. Does yours have a suspension seat?

Yes suspension with spring on it. The seat switch is leveled like.
Took advice printed the 3800 wsm

 

[HillMowpow]

Yes suspension with spring on it. The seat switch is leveled like. It flips back and forth so one can work under the seat.
Took advice printed the 3800 wsm

 

[old and tired]

WSM = Work shop Manual (aka Service manual)

Kubota #9Y011-13194 L2800, L3400, L3700SU Shop Manual

$139.62
Usually ships in 20-30 business days

For that price, I would expect hand delivery on the same day it was ordered...

 

[HillMowpow]

What keeps bringing ya to the glow plugs? I wouldn’t think a glow plug is what’s stopping it from starting. Obviously maybe in cold weather but now? Could try pulling fuse or disconnecting glow plugs altogether then try starting to see if they are drawing to much or changes anything. No clue if this is a good idea but it’s an idea. Not really a reading but more process of elimination.
Given the amount of testing you’ve done I’m gonna assume you have checked and cleaned all grounds and connections/harnesses for proper connection. Might not be a bad idea to dbl check your seat safety bypass. Pto safety switch might be another place to look around. Neutral safety switch maybe.

Yes terminals are all clean. And connectors good. Where is the PTO safety switch? Where is Neutral safety switch? I'll check seat again.

 

[old and tired]

So you have a HST model, the PTO safety switch is on the bottom of the bracket that attaches the On/Off bracket to the wheel fender.

Neutral safety switch is for the manual model... I don't know about that model.

This is what I do when I have a safety switch "issue". Hold the key in the "ON" position (keep it there until it starts), on HST model (sorry I don't know Manual switches), slowly press the HST peddle forward and backwards (repeat that again slowly). Then move the PTO lever forward and back as far as they go. Then reach under the left side of the seat and hold down the seat switch (or rock your butt around in the seat).

The clutch safety switch is right by the clutch, make sure it's connected - if there is a break in the line, it will not start... Good luck.