Kubota broke then repaired itself!

   / Kubota broke then repaired itself! #1  

orezok

Elite Member
Joined
Jan 30, 2004
Messages
3,489
Location
Mojave Desert, CA
Tractor
Kubota B7800
My B7800 suddenly would not start in the middle of a grading project I was doing. I was shutting it down while doing grad checking. I checked the usual culprits, PTO on, pedal not centered etc. No luck. The solenoid would click, but the starter would not engage or turn. I suspected that one of the safety switched could have failed so I put it in neutral and jumped the starter. Fired right up!

I left it running for the rest of the day while I finished my project.

I took it back to the barn when done and shut it down. I gave it another try to start with the key and it fired up a couple of time without problem.

Hooray, Kubotas can heal them selves!
 
   / Kubota broke then repaired itself! #2  
I really hate to rain on your parade, but that is the classic symptom of a poor electrical path from your key switch, thru all your safety switches to the starter solenoid. One day it starts, the next day it doesn't, and the third day it only starts when you cycle the key a couple of times. The solenoid click that you hear probably results from not enough power getting to it. Try putting a volt meter on the solenoid lead and read the voltage when you hear it click. It should be very close to the battery voltage.
 
   / Kubota broke then repaired itself! #3  
It sounds to me like your starter solenoid is on its way out. The contact area inside the solenoid has finally burnt itself away enough that you don,t get a good contact when it is energized. If you are capable of changing it out yourself, pick up a new solenoid, and have it on hand, so you can change it out when the old one finally quits for good.
 
   / Kubota broke then repaired itself! #4  
Of the two posts above either A or B could be correct. It is also very possible that A caused B. I have seen a new solenoid or starterr fix the symptom, but only temporarily. Then the voltage drop issue was properly diagnosed and cured.
 
   / Kubota broke then repaired itself! #5  
My B7800 suddenly would not start in the middle of a grading project I was doing. I was shutting it down while doing grad checking. I checked the usual culprits, PTO on, pedal not centered etc. No luck. The solenoid would click, but the starter would not engage or turn. I suspected that one of the safety switched could have failed so I put it in neutral and jumped the starter. Fired right up!

I left it running for the rest of the day while I finished my project.

I took it back to the barn when done and shut it down. I gave it another try to start with the key and it fired up a couple of time without problem.

Hooray, Kubotas can heal them selves!

Have you cleaned battery terminals, and ground lead end?
 
   / Kubota broke then repaired itself! #6  
One thing we can ALL agree upon, is the problem will return.

Pull on those big red and black wires that are attached to the battery terminals after you get the off of the battery posts for the cleaning. One or both of them may just come off in your hands. It is not uncommon for the copper to be "rotten" inside of the plastic insulation. Just white/greenish powder left. I keep harping about No-Ox-ID. Been talking about it here on this board for years.
 
   / Kubota broke then repaired itself! #7  
i use the red and green coated rings under all my batteries, and all batteries i install in generator systems. Mine are made by Exide. I also use battery top coat spray made by Krylon ( i use both the cleaner and protector sprays. these products are amazingly good. Since i started using them 5 years ago i have had ZERO corroded battery posts on all my installs).
 
   / Kubota broke then repaired itself! #8  
One thing we can ALL agree upon, is the problem will return.

Pull on those big red and black wires that are attached to the battery terminals after you get the off of the battery posts for the cleaning. One or both of them may just come off in your hands. It is not uncommon for the copper to be "rotten" inside of the plastic insulation. Just white/greenish powder left. I keep harping about No-Ox-ID. Been talking about it here on this board for years.

I understand NO-Ox-ID is conductive. Do I have to worry about short circuits? At what voltage and or distance is it save to use? Would you use it on connectors with positive and negative next to each other?
 
   / Kubota broke then repaired itself! #10  
I understand NO-Ox-ID is conductive. Do I have to worry about short circuits? At what voltage and or distance is it save to use? Would you use it on connectors with positive and negative next to each other?

If it is conductive, it is news to me. I have been using it on mobile antenna parts for years. I have used it on all sorts of electrical connectors. I can't say what it would do at voltages over 120 volts, as I haven't tried it there, but normal mobile voltages under 52 volts no problems. I started using it as it was sent along on Globe stationary battery plants for PBX's for many years. After applying it to every exposed battery terminal on the battery plant, there were always lots left over in the jars. I took them home and started using it on all of my vehicles and soon started using it to prevent corrosion on antennas, and even coated the screws I drilled into automotive bodies. I learned that if you coat a self tapping screw threads before you run it into automotive sheet metal when you take it out years later, it will not be corroded. Including screws driven into transmission hump mounted bracket which are exposed to water and road salt for years. This normally eats screws down to nothing but rust in a few years, but not coated with No-Ox-Id.
 
 
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