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Back in 2019 when I acquired my 1985 JD 111, I had several electrical/charging issues that I solved with help from several members on this forum.

I've now got some new issues involving the PTO clutch and possibly the mower deck.

I can run the tractor all day hauling wood/debris/mulch/gravel in the trailer with no problem. I've measured the battery voltage while running and at high throttle, it's usually between 13 and 14 volts.

I noticed after mowing for about 1 to 1.5 hours the battery voltage is near 12.2 - 12.4 volts. I checked the battery with the PTO disengaged and the voltage immediately started climbing. When I engage the PTO the battery voltage slowly decreases until the mower dies.

Can anyone point me in a direction to try to track down the problem?

Thanks in advance.

Barry
 

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Sounds like pto field coil is failing. Disconnect plug at pto and check resistance through the coil. Should be around 4 ohms. If near 2 ohms coil is pretty much shot.

Engine heat will warm the pto as will current flowing through the pto when in use. This warming caused the wiring to expand. After shutting down, wires cool and contract. This expansion/contraction makes the wires rub against each other and the thin varnish type insulation gets worn off. This reduces the resistance and allows more current to flow through the coil, drawing system voltage down.

Check coil resistance and report back! Bob
 

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First, you are mowing with the engine at top speed?

If not, you want to...
If so, it sounds like the alternator can't keep up with the power that the pto uses.

Some things it could be:
-engine may not be original, and the replacement engine might have a alternator that doesn't put out enough power
-regulator could be wrong, can't put out enough power
-pto clutch/wiring could have a problem so it draws too much power
 

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I had to replace the diode in my 111H. 111H diode replacement I sold the mower last year. IIRC the original 11hp engine had a Stator with a single wire and a green connector. The diode was in another wire between the green connector and the solenoid. If your Stator has 2 wires it probably one of the lower powered ones from a later engine.
Cannon
 

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I had to replace the diode in my 111H. 111H diode replacement I sold the mower last year. IIRC the original 11hp engine had a Stator with a single wire and a green connector. The diode was in another wire between the green connector and the solenoid. If your Stator has 2 wires it probably one of the lower powered ones from a later engine.
Cannon
 

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Discussion Starter #6
Sounds like pto field coil is failing. Disconnect plug at pto and check resistance through the coil. Should be around 4 ohms. If near 2 ohms coil is pretty much shot.

Engine heat will warm the pto as will current flowing through the pto when in use. This warming caused the wiring to expand. After shutting down, wires cool and contract. This expansion/contraction makes the wires rub against each other and the thin varnish type insulation gets worn off. This reduces the resistance and allows more current to flow through the coil, drawing system voltage down.

Check coil resistance and report back! Bob
I checked the coil resistance after blowing all the crud off with a compressor.

it measured 3.2 ohms cold. I then engaged the PTO and measured battery voltage with full throttle and it was slowly discharging.
With PTO disengaged, the battery started charging again.

With the clutch cleaned up, it looks almost new.

Next step will be to check all PTO associated wiring.
 

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3.2 ohms is getting to the bottom of the spec, 3.0 ohms, but to me, it's still within the specification. I'd try to find info on charging system as it sure sounds like alternator can't keep up. Bob
 

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3.2 ohms is getting to the bottom of the spec, 3.0 ohms, but to me, it's still within the specification. I'd try to find info on charging system as it sure sounds like alternator can't keep up. Bob
I agree with Bob. That B&S gear may keep the battery up for starter and light but not the clutch.
 

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Any specifications for this part number other than it meets B&S specification. Does it meet JD specifications for your tractor would be the question. I could find non doing a search.
My communication with B&S sales indicates that stator 592828 is the replacement for many other part numbers.

I may have found a source for stators 696578 and 393809 (both 3.0 amp predecessors of 592828). These are listed in B&S alternatorspecifications.pdf.

I’ve been trying to get confirmation of compatibility from B&S tech support, but they’re not too forthcoming.

I’ll keep trying to get info, but may at some point take a flyer on one of the parts I found.
 

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When I check with Deere a few years ago. They had a listing for two different ones. If you still have the old one they should be able to tell you what's needed.
 

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I haven't yet gotten any response from Briggs and Stratton.

I've just completed running a bunch of tests.

Here are the results:
  1. Diode indicates good on the diode test feature of my meter (0.556 forward voltage drop; over range with leads reversed)
  2. PTO Clutch resistance is 3.2 ohms
  3. DC voltage out of the isolated stator is approximately 17.5 volts
  4. With battery fully charged after a night on the trickle charger, the tractor starts immediately and battery charges continuously with PTO OFF.
  5. Stator is putting out 1.7 amps DC when everything is connected and PTO OFF.
  6. Stator is putting out 1.7 amps DC when everything is connected and PTO ON.
  7. When PTO is ON, battery discharges continuously until everything shuts down.
 

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Only getting 1.7A out of the charging circuit means it's not powerful enough to run the PTO, which I believe generally need about 5-6A.

So
-engine is not original, and has too small of a charging system
-charging system was fixed with the wrong parts/incorrectly
 

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Discussion Starter #16
Thanks dave_r.

That’s the same conclusion I reached.
Back in 2019, when I first joined the forum, I talked about the charging issue. The outfit that sold me the 111 replaced the alternator and botched the job. They installed it upside down so the flywheel sheared off the output wire. On top of that, they routed the alternator output wire behind the starter motor, but pinched the wire so it grounded the alternator and fried it.
When I showed him the damage, he wouldn’t look me in the eye. He just said “Nice troubleshooting job”.

I live in a small town, and needless to say, a lot of folks have heard the story.

In any case, I replaced the stator with the one offered by another dealer and as you stated, it’s not strong enough to do the job.

I’m trying to source the proper stator for my engine, but haven’t yet identified it.

Briggs and Stratton are sliw to respond.

The alternator I installed was 592828

the ones I’m looking at are 676578 or 393809.
 

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From the pdf frogmore posted, that 393809 stator may not be powerful enough either (3A) and 676578 doesn't come up with good matches via google to figure out what amps it supports.

I think you'll want one that produces at least 5A (personally I would either figure out what the engine originally came with, either via John Deere's parts list or briggs&stratton, or select one that produces at least as many amps as what the pto uses [you seem handy with an ammeter, easy enough to get that value]).
 

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It looks like all the high amp ones need a regulator. 15A will cook your battery if you are not using the PTO for a long time, so good idea to have a regulator.
 

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Oops! I had a typo on the part number of one of the alternators I'm looking at. It should be 696578. That one also shows 3.0A in the document that Frogmore posted.

I spoke to the previous owner of the tractor. He said that he bought it new in 1986 and the engine has never been changed. I've used the serial number of the tractor (M00111331730) to try to get info about the original parts, but I haven't scored any info yet.

I also can't find any physical evidence that the tractor had a regulator installed. I'm pretty certain that it had a DC-only alternator from the start.

Here's the wiring diagram that I found some time ago:
 

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