No start on L4200

[Lmbaunack]

Hello everyone, so I recently purchased a Kubota l4200. I am going through all the wiring and noticed that they had the starter red wire going straight from the main switch to the starter and bypassing everything. I disconnected that wire and reconnected the original wire, however it will gain lights to the dash and then when I go to start at the voltage drops on everything. My first assumption is a safety switch, however I bypass them I believe and it's doing the same thing. My next thought was a relay so I replace the glow relays as well as the starter relay and the problem still persists. The workshop manual electrical diagram is so poor that I cannot see exactly where the routes go on the electrical lines. Any thoughts? Some things I noticed, the alternator hums when the ignition is in on position and there is power going to it as well as power going to the black and white cable going to the starter from the switch through the relay. When you turn the key to start, that is when the voltage drops. Thoughts? Anyone have a photo of a solid electrical diagram of the starting system?

 

[Roadworthy]

Voltage normally drops somewhat when the starter is energized. Depending on the vehicle power may be interrupted to all other circuits when the starter is energized. Begin your quest by fully charging the battery then having it load tested. Clean the battery terminals well. Clean the connectors well. Replace connectors onto terminals and tighten securely. If you can move them they're not tight enough. Follow the ground lead to the frame. Clean and tighten there. I would go through this exercise prior to doing much troubleshooting. If you want to pursue your problem further you may have to purchase a manual.

 

[Lmbaunack]

Voltage normally drops somewhat when the starter is energized. Depending on the vehicle power may be interrupted to all other circuits when the starter is energized. Begin your quest by fully charging the battery then having it load tested. Clean the battery terminals well. Clean the connectors well. Replace connectors onto terminals and tighten securely. If you can move them they're not tight enough. Follow the ground lead to the frame. Clean and tighten there. I would go through this exercise prior to doing much troubleshooting. If you want to pursue your problem further you may have to purchase a manual.

Got it, I had put a new battery on it first thing as the original was dead dead. I'll continue to go through line by line of the starting circuit and I have a good quality OEM manual on order. Thanks!

 

[CoyPatton]

Got it, I had put a new battery on it first thing as the original was dead dead. I'll continue to go through line by line of the starting circuit and I have a good quality OEM manual on order. Thanks!

With the wire (I understand from the ignition switch bypassing all safety switches) start the tractor?
If yes to this question. Which I am not sure of from the initial post. You can eliminate the battery and cable end issues, that were suggested and that I often suggest!
And you have bypassed each safety switch in the original wiring harness, and it still does not spin the engine, I suspect the ‘pop’ you heard is a hard short to ground of that wiring circuit. These can be a pain to locate. If this is what you are encountering, try starting it in the dark with as much stuff cleared where you can see the harness. (Much easier to type than do). Watch for the tell-tale spark or glow where it should not be (extra sets of eyes can be helpful). It could be any where from a loose connection to compromised insulation to a loose nut.

 

[Lmbaunack]

With the wire (I understand from the ignition switch bypassing all safety switches) start the tractor?
If yes to this question. Which I am not sure of from the initial post. You can eliminate the battery and cable end issues, that were suggested and that I often suggest!
And you have bypassed each safety switch in the original wiring harness, and it still does not spin the engine, I suspect the ‘pop’ you heard is a hard short to ground of that wiring circuit. These can be a pain to locate. If this is what you are encountering, try starting it in the dark with as much stuff cleared where you can see the harness. (Much easier to type than do). Watch for the tell-tale spark or glow where it should not be (extra sets of eyes can be helpful). It could be any where from a loose connection to compromised insulation to a loose nut.

Thanks! Yes, If I run wire from switch to starter direct it works. I'm going to test the relays even though they are new

 

[CoyPatton]

Thanks! Yes, If I run wire from switch to starter direct it works. I'm going to test the relays even though they are new

Go ahead and check your relays, but I think you will find your issue is in the integrity of the factory wiring harness.
I suggest that you start at one end (starter or ignition switch) and run ohm test on each section of the harness. While doing so check the safety switches—for function electrically and function. A safety switch may be good electrically, but fail a physical function test (not unusual for HST neutral safety switches). However, the pop you mentioned really causes me to think of an arc to ground.
With patience it can be fixed.

 

[Lmbaunack]

Thanks everyone! I found that a relay that looked identical to another was reversed and the key timer relay was where the ignition relay was supposed to go..... EASY FIX

Then I broke the brake rod adjusting it. Poor tractor never had a bolt turned for maintenance before I don't think.