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Discussion Starter · #1 ·
Hi! I have a John Deere 111 from the 1980s and the pto clutch was not engaging. I disconnected it from the default wire, and tested the wire with a multimeter. There appears to be 12v coming from the battery to the lead when the key is turned and pto switch engaged. I tested the clutch with an ohmmeter, and it shows about 4 ohms of resistance. When I connect the clutch directly to the battery, bypassing the normal wire, it goes clunk, showing the internal workings of the clutch are possibly ok. So my question: even though there's 12 volts coming down from the battery to the wire that connects to the clutch, do you think there's some problem between the battery and the wire that connects to the clutch's leads? Perhaps there's something about the wire that dampens the amount of amperage (some source of resistance) happening, even though it shows 12 volts? How can I test this and find the culprit? If I can't figure it out, can I just hotwire the clutch, i.e, connect the clutch lead directly to the battery and put in a toggle switch so I can manually turn the blades on and off? If so, any specs on that? i.e. a 10 amp switch, for example? Any advice is welcome! I'm an amateur electrical/small engine person.
 

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Had a jd111 years ago.
The actual connector went bad. Also not sure if you are aware.. proper maintenance on clutch was to adjust the air gap using feeler gauge. If I remember correctly was supposed to be 0.015 - 0.018 inch.
If you didn't adjust the clutch would slip and overheat. won't engage either when hot.

RoadrunnerII

Sent from my SM-A515F using Tapatalk
 

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2008 John Deere LA135
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You need to test the ground side of the clutch coil. You have 12 volts at the feed side, and the clutch actuates when connected directly to + and - at the battery, so you need to test the ground portion. Also, check the terminals on the connector for corrosion and make sure they have enough tension when they are mated.
 

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Well, I do know this: there is a section in the JD Technical Manual 1206 -- ELECTRIC PTO CLUTCH.
There are some testing procedures.
Page 50-30-1:
"The electric PTO clutch requires approximately 4 amps current to operate properly.
A faulty clutch switch, loose wiring, short circuit or defective battery can appear as clutch failure."
Page 50-30-3:
"Insert a (0.33 mm) 0.013-in. feeler gauge......"
Wiring been messed with? Seat safety-switch OK?
Does it operate at all? Maybe will work then not when it's very warm - might work again after it has cooled?
Good Luck. Think a new one of those entire electric PTO clutches from JD costs over 240 bucks.
 

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Discussion Starter · #5 ·
Thanks everyone! It's quite a fun project (and frustrating, but that's part of the fun I guess). I will let you know how some of these things work out. The funny thing is that it took me about 15 minutes to get the seat safety switch unhooked to test it -- the connector was soo hard to get off without destroying it. I bypassed it but that doesn't seem to fix the problem. So now I'm thinking it's either extra resistance being introduced by the starter switch or the pto switch itself. I'll need to figure out how to check them -- that's next weekend's job. I think the trick will be bypassing each one in turn and trying to see if I can get 4 amps to the clutch. I see that there's about 4-ish ohms when I try to pass current through the clutch, so if v=ir, I guess i = 3-4 so that makes sense.
 
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