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1968 John Deere 112H: update and more questions

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#1 alexcole OFFLINE  


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Posted September 03, 2011 - 06:45 AM

Thanks for the help so far, previous thread here: http://gardentractor...ont-start-7446/

Update: I charged the battery, replaced the three wire plug and voltage regulator, put new plugs on the wires leading to the PTO neutral safety switch, and replaced the PTO neutral safety switch. After putting everything back together, turned the key and.................nothing. Not a click, not a whir, nothing. So after some further thought and conversation with co-workers, I used a screwdriver to jump the starter solenoid, and voila! Drove around and cut the grass for about half an hour. What a thrill! Then, I got into some long grass and it either bogged down and quit (didn't think that was possible on a John Deere) or it coincidentally chose that moment to die. Either way, when I tried to jump starter solenoid with the screwdriver again, it wouldn't start- battery didn't have enough juice. So I pushed it back to the shed (all 638 lbs of it!) and put the battery back on charge. This morning, battery was charged up, and it started up again for me when I jumped it with the screwdriver.

Questions: Pretty obvious that I need a new solenoid, right? But why is the battery dying? I didn't have the headlights on, why would there be a drain on the battery? Shouldn't I be able to start it up and effectively remove the battery and have it keep running, or am I missing something big and obvious here? Also feel that whatever should be charging the battery (I would think alternator, but this mower may pre-date that and have a generator in it??) isn't doing it's job.

Any help is appreciated. Thanks in advance, Alex.

#2 JDBrian OFFLINE  


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Posted September 03, 2011 - 07:53 AM

Alex, it sounds like you have done a lot of work to get this far. I don't have an electrical diagram for the 112 but iI will assume it is similar to the 200 series. There should be a circuit breaker and perhaps an ammeter, if one is installed, as well as the ignition switch run contacts between the regulator output and the solenoid/battery connection. You should verify that you have a good connection between the regulator and the battery + terminal. Disconnect the battery + to do this test with an ohmmeter. You also need to verify that you have a good connection from the case of the regulator back to battery - terminal. A bad connection at any of these points will prevent the charging circuit from operating properly.
On the starting side, any safety interlock switches will be between the ignition switch and the solenoid, such as the neutral switch or PTO switch. You replaced the PTO switch but you need to verify that it is connected so that the interlock contacts are closed when the switch is in the off position. This allows the starter to work only if the PTO switch is off. Try these things and let us know what you find.

#3 Ol Blue OFFLINE  

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Posted September 07, 2011 - 11:47 AM

I didn't see a rule against posting the above picture. If it isn't allowed, I apologize. Please let me know and I'll remove it.

Not charging:
Loosen positive battery cable, start the engine and pull positive cable off the battery. If the engine quits, the charging system is not working. With the cable off and the engine (hopefully, still) running, you can also check the cable for up to 14.3volts from the regulator.

If the engine quits, check the white wire at the switch. It should read 12volts or more when you turn the key on. This comes from the battery, so the engine does not need to be running. If OK, also check at the 3-wire connector to make sure that same wire isn't broke between the switch and connector.

If OK, there's a bigger problem with the stator, field windings, or other depending on your engine (Kohler or Tecumseh) and the tractor's serial number.

Not starting:
By jumping the battery cable to the starter cable at the solenoid, you're also bypassing the neutral safety switch, and the PTO safety switch. Both of these safety switches are "between" the keyed ignition switch and the solenoid. Turn the key to start (not just run) and check the small purple wire for 12volts. If there is 12volts there, the safety switches are working and the solenoid is bad. If there is not 12volts there, start checking the input and outputs of the safety switches and the "S" start post at the keyed ignition switch for 12volts with the key on, transmission in neutral, and PTO off.

Battery draining:
Fix the charging first and hopefully there really isn't a draining problem.

Hope this helps.

Edited by Ol Blue, September 08, 2011 - 09:32 AM.

  • Texas Deere and Horse said thank you