Charging circuit drawing too much current

[Arkie]

Do you have a 3 wire stator per the diagram posted with those colors for the stator wires?

Do you have any idea how you could be connecting the diode to the wrong stator output wire????? Green is sometimes (ususally) the color for the dynamic brake on a Kohler engine which the ignition switch grounds when turned off to brake the engine faster.

If you are sure you are using the correct stator charge wire and the engine is not over speeding at idle. Your AC voltage is too high due to a bad stator if you are using the correct stator charge wire. The stator brake winding might be shorted to the charge winding in the stator. (and a ohmmeter reading will not show such because all 3 windings have the common ground connection)

Are your headlights connected and do they operate when the engine is running? If not connect them and test.
Reason I ask is some eq leave the headlights connected to the stator all time, not switched and this keeps the stator voltages lower and the charge amps lessened. Even though the lighting uses a separate stator winding the AC charge winding voltages will be less due to the stator lighting load. (some low amps charge systems use this method)

[rms59]

The Kohler diagram.
https://i.imgur.com/08Cj187.png
I understand the confusion on the wire colors but the stator has only two wires. A black one and a green one. The black one measures 14V (lighting) and the green one 28V (charging). Although my brother (tractor owner) swears the yellow wire was once connected to the diode before it all melted. I left it unconnected since the other end goes to a relay that only shorts the stator to gnd if the operator leaves the seat before the blades stop. I can only assume it works against the magnetic field to stop the engine quicker. As far as WOT, I don't have a tach but I can assure you that the RPM is about the same as his other tractor and seems normal. The governor is working. Even then it still draws 6 amps at idle when it shouldn't on a fully charged battery.

Interesting thing is that this guy seems to have had the same problem on the same engine
and the same color wires.

https://www.lawnmowerforum.com/showthre ... r-Question

I couldn't get to my brothers to work on that tractor today but mangaged to check my Husqvarna YTH22V46 which also has only two stator wires. Unlike the Craftsman, there is no stator brake thus no relays or extra wire. This is the wiring diagram for that.

https://www.bing.com/images/search?view ... vt=0&eim=0

On the Husqvarna, with everything connected normally and engine running at 3/4 throttle, I measured the following:
28VAC on the Anode (which is connected to one of the two stator wires.)
15VDC on the Cathode (battery connected)
20VAC also appeared on the Cathode as the AC component.
15VAC on the other stator wire connected to lights which were off.
1.2amp with meter in series with cathode wire. (The battery was initially used to start tractor).

The lighting circuit of the stator measured 15VAC with lights off.

I'm at a point where I believe it has to be the stator but just don't know why. Back at it tommorrow....

[Arkie]

Yes, appears to be something wrong with the stator, but too much voltage does not sound logical. Usually it's too low or none at all.

Before I spent $60 or so for a replacement stator I would get me about 4, 1 ohm 10 watt resistors and connect in series with the Diode or Stator output to reduce the amps to 2 amps at max throttle.

With 4 of these you can PROBABLY series/parallel a combination to get the charge amps correct. Start out with all 4 in series then if charge amps too low jump them out one at a time until you get in the ball park. Be careful of the resistors because they will get very hot and will burn meat and melt plastic. Wattage of one resistor in series will be 6 watts or more so they are going to get hot, but you can series/parallel them to keep the resistor dissapiated heat down

Price about $4.50 for 4.

https://www.radioshack.com/products/rad ... tor-2-pack

You really do not need any trickle charge at low rpms, just go for 2 amps at max throttle.

I would use a 15 amp fuse in series with all in case a diode shorts you will not have a melt down flame out. Go ahead and use your larger amp diode while testing.

[bgsengine]

The Kohler diagram.
https://i.imgur.com/08Cj187.png
I understand the confusion on the wire colors but the stator has only two wires. A black one and a green one. The black one measures 14V (lighting) and the green one 28V (charging). .

So which is it? n an earlier post, you seemed to be saying you were getting 40 VAC at the green wire at WOT... Only measurement that *matters* is the one at 3600 RPM (WOT) - it is pointless to check output voltage at the stator anywhere else than normal operating RPM, especially when diagnosing a charge output issue .. So, do you get 28V at WOT or 40V ? If it is 28VAC at 3600 RPMs then your half wave rectified voltage (via Diode) should only ever be 14 volts DC (up to 14.8 volts) .. 40VAC would be giving nominally 20 VDC at full throttle - in any case.. anything over 15 volts is going to FRY your battery if it is allowed to continue.. so.. If your measurements are correct, something ain't right - So you either got engine (flywheel magnets) spinning too fast, or you got extra voltage leaking from other stator coils (as was suggested earlier), or your test meter is off somehow. When you had flywheel off did you check the magnets to see if any , by some chance, might have been loose? (spacing between magnets) They've been known to separate and "cluster" together, so it's within realm of possibility (though Ive no idea how it might happen) an odd cluster of magnetism could be multiplying voltage.. though the ones I found with magnets like that were diagnosed due to LOW output voltage, I suppose a theory could be put out that same thing could cause an over-voltage..

However - Any meter readings are and will always be suspect until you are able to actually check engine RPMs (simple maintenance tachs are accurate enough for 4-stroke single cylinder work, and Ive seen them for under $20 these days)

[KE4AVB]

rms59,

The lighting wire is optional per the SM and yes I had one unit I repair last year where the yellow lead was connected to the black lead at the diode anode then another black lead attached to the cathode which continued on to the battery. Green lead is definitely on the stator brake circuit.

Humor me here disconnect the green lead, move the diode to the black lead observing the correct polarity, and connect this new setup to the battery. Then test for both the correct voltages and amp draw at full throttle. At idle there may not be enough voltage to produce a charging current but this to be expected with nearly fully charged battery.

[Arkie]

The Kohler diagram.
https://i.imgur.com/08Cj187.png
I understand the confusion on the wire colors but the stator has only two wires. A black one and a green one. The black one measures 14V (lighting) and the green one 28V (charging). .

So which is it? n an earlier post, you seemed to be saying you were getting 40 VAC at the green wire at WOT... Only measurement that *matters* is the one at 3600 RPM (WOT) - it is pointless to check output voltage at the stator anywhere else than normal operating RPM, especially when diagnosing a charge output issue .. So, do you get 28V at WOT or 40V ? If it is 28VAC at 3600 RPMs then your half wave rectified voltage (via Diode) should only ever be 14 volts DC (up to 14.8 volts) .. 40VAC would be giving nominally 20 VDC at full throttle - in any case.. anything over 15 volts is going to FRY your battery if it is allowed to continue.. so.. If your measurements are correct, something ain't right - So you either got engine (flywheel magnets) spinning too fast, or you got extra voltage leaking from other stator coils (as was suggested earlier), or your test meter is off somehow. When you had flywheel off did you check the magnets to see if any , by some chance, might have been loose? (spacing between magnets) They've been known to separate and "cluster" together, so it's within realm of possibility (though Ive no idea how it might happen) an odd cluster of magnetism could be multiplying voltage.. though the ones I found with magnets like that were diagnosed due to LOW output voltage, I suppose a theory could be put out that same thing could cause an over-voltage..

However - Any meter readings are and will always be suspect until you are able to actually check engine RPMs (simple maintenance tachs are accurate enough for 4-stroke single cylinder work, and Ive seen them for under $20 these days)

Per the wiring diagram, 28vAC at 3600 rpms' It also indicates this is open circuit voltage, charging system disconnected from the battery. This is your specs for checking the charging system. You can get a tach from flea bay for less than $15.
If WOT is more than 3600 expect the AC stator voltage to be higher. You cannot assume that WOT is not more than 3600 in your case.
With 28vAC and half wave rectification the output voltage should be for that stator system around 14.8volts or not over 3 amps to charge a 12v bat. (that is the max specs for that stator)

[rms59]

Yes, appears to be something wrong with the stator, but too much voltage does not sound logical. Usually it's too low or none at all...

I don't want to use the resistors because, as a technical guy, I want to know what is bugging that circuit. It's become a personal thing now.

The Kohler diagram.
https://i.imgur.com/08Cj187.png
I understand the confusion on the wire colors but the stator has only two wires. A black one and a green one. The black one measures 14V (lighting) and the green one 28V (charging). .

So which is it? n an earlier post, you seemed to be saying you were getting 40 VAC at the green wire at WOT... Only measurement that *matters* is the one at 3600 RPM (WOT) - it is pointless to check output voltage at the stator anywhere else than normal operating RPM, especially when diagnosing a charge output issue .. So, do you get 28V at WOT or 40V ? If it is 28VAC at 3600 RPMs then your half wave rectified voltage (via Diode) should only ever be 14 volts DC (up to 14.8 volts) .. 40VAC would be giving nominally 20 VDC at full throttle - in any case.. anything over 15 volts is going to FRY your battery if it is allowed to continue.. so.. If your measurements are correct, something ain't right - So you either got engine (flywheel magnets) spinning too fast, or you got extra voltage leaking from other stator coils (as was suggested earlier), or your test meter is off somehow. When you had flywheel off did you check the magnets to see if any , by some chance, might have been loose? (spacing between magnets) They've been known to separate and "cluster" together, so it's within realm of possibility (though Ive no idea how it might happen) an odd cluster of magnetism could be multiplying voltage.. though the ones I found with magnets like that were diagnosed due to LOW output voltage, I suppose a theory could be put out that same thing could cause an over-voltage..

However - Any meter readings are and will always be suspect until you are able to actually check engine RPMs (simple maintenance tachs are accurate enough for 4-stroke single cylinder work, and Ive seen them for under $20 these days)

Both. The 28VAC was initially measured with engine at idle and I never had a reason to check it at WOT because it was already 6 amps at idle and solder melting 9 amps at mid throttle range. During following tests I did go to WOT and the voltage across the battery was measured at 40VAC. Since you mentioned accuracy of the meter I put my Simpson Analog 260 and my Craftsman digital RMS meter across the output of a 24VAC wall transformer and then across the 120VAC line and got exact readings. Then I started checking some 1% resistor values just for kicks and got same results. I'm glad you brought that up since I haven't checked calibration in a long time so now I'm happy that I did read that 40V correctly.

Borrowed a meter and at WOT I read 3430 RPM and 1510 at idle. Don't know if that is good or bad but the blades turn fast enough.

The flywheel magnets (6 of them) are clean and tightly bonded. I took a screwdriver and held it about 3/4 inches away from each one and they pulled in hard. The stator has no scrape marks, nicks, or discoloration.

rms59,

The lighting wire is optional per the SM and yes I had one unit I repair last year where the yellow lead was connected to the black lead at the diode anode then another black lead attached to the cathode which continued on to the battery. Green lead is definitely on the stator brake circuit.

Humor me here disconnect the green lead, move the diode to the black lead observing the correct polarity, and connect this new setup to the battery. Then test for both the correct voltages and amp draw at full throttle. At idle there may not be enough voltage to produce a charging current but this to be expected with nearly fully charged battery.

With the green (and yellow that goes to the operator relay) not being used, I connected the diode to the black wire. At idle there was 12.0 volts across the battery terminal and at WOT it got to 12.7

The Kohler diagram.
https://i.imgur.com/08Cj187.png
I understand the confusion on the wire colors but the stator has only two wires. A black one and a green one. The black one measures 14V (lighting) and the green one 28V (charging). .

So which is it? n an earlier post, you seemed to be saying you were getting 40 VAC at the green wire at WOT... Only measurement that *matters* is the one at 3600 RPM (WOT) - it is pointless to check output voltage at the stator anywhere else than normal operating RPM, especially when diagnosing a charge output issue .. So, do you get 28V at WOT or 40V ? If it is 28VAC at 3600 RPMs then your half wave rectified voltage (via Diode) should only ever be 14 volts DC (up to 14.8 volts) .. 40VAC would be giving nominally 20 VDC at full throttle - in any case.. anything over 15 volts is going to FRY your battery if it is allowed to continue.. so.. If your measurements are correct, something ain't right - So you either got engine (flywheel magnets) spinning too fast, or you got extra voltage leaking from other stator coils (as was suggested earlier), or your test meter is off somehow. When you had flywheel off did you check the magnets to see if any , by some chance, might have been loose? (spacing between magnets) They've been known to separate and "cluster" together, so it's within realm of possibility (though Ive no idea how it might happen) an odd cluster of magnetism could be multiplying voltage.. though the ones I found with magnets like that were diagnosed due to LOW output voltage, I suppose a theory could be put out that same thing could cause an over-voltage..

However - Any meter readings are and will always be suspect until you are able to actually check engine RPMs (simple maintenance tachs are accurate enough for 4-stroke single cylinder work, and Ive seen them for under $20 these days)

Per the wiring diagram, 28vAC at 3600 rpms' It also indicates this is open circuit voltage, charging system disconnected from the battery. This is your specs for checking the charging system. You can get a tach from flea bay for less than $15.
If WOT is more than 3600 expect the AC stator voltage to be higher. You cannot assume that WOT is not more than 3600 in your case.
With 28vAC and half wave rectification the output voltage should be for that stator system around 14.8volts or not over 3 amps to charge a 12v bat. (that is the max specs for that stator)

Yep. Initially No Load is how I measured the 28 and 14 to gnd.


When I first got to look at this Craftsman tractor after the initial diode meltdown, my brother already cleaned up the wiring so I can't verify how it was connected. But on my Husqvarna I can clearly see two wires coming from the stator with one going to a small diode, the ammeter, a fuse, and then to the battery while the other wire goes directly to the lights. There is no third wire. Since both the Craftsman and Husqvarna schematics I linked to show the charging and lighting circuits to be almost identical in nature I'm 99% sure the 2-lead Craftsman is wired the same way.

My brother is ordering a new stator (around $30) on a roll of the dice that this will solve the problem. This whole thing to me is like bizzaro world physics where a broken egg falls off the counter and lands on a concrete floor becoming a whole egg again. It just doesn't make sense.

I promise to get back with the results in a few days. Thanks to all for the insightful help and I have to tell you this is the only help forum that I didn't have to wait days for responses. You guys are great and I will get back.

[bgsengine]

When I first got to look at this Craftsman tractor after the initial diode meltdown, my brother already cleaned up the wiring so I can't verify how it was connected.

Ahhhh! Maybe getting somewhere..

But on my Husqvarna I can clearly see two wires coming from the stator with one going to a small diode, the ammeter, a fuse, and then to the battery while the other wire goes directly to the lights. There is no third wire. Since both the Craftsman and Husqvarna schematics I linked to show the charging and lighting circuits to be almost identical in nature I'm 99% sure the 2-lead Craftsman is wired the same way.

You DO have a green wire then? Which if our info is correct is a stator brake.. And since you mention the wiring was "cleaned up" I would wonder if perhaps 2 wires (stator brake and charge output) fused together (a short in a charge circuit melts your charge wire into the green wire and burns off the charge wire before it's all done with, for example)

My brother is ordering a new stator (around $30) on a roll of the dice that this will solve the problem. This whole thing to me is like bizzaro world physics where a broken egg falls off the counter and lands on a concrete floor becoming a whole egg again. It just doesn't make sense.

So get that replacement put in and assuming that solves your problem, I'd be taking a VERY close look at the old stator and windings to see if it wasnt jusrt a case of 2 circuits getting melted together during the short-out event...

I promise to get back with the results in a few days. Thanks to all for the insightful help and I have to tell you this is the only help forum that I didn't have to wait days for responses. You guys are great and I will get back.

Call it a learning experience, but with experience, you'll quickly find most all service manuals will direct you to check VAC at WOT... and since you'd then have found the 40VAC output right there, might have saved a ton of time messing with the wrong side of things, because there's no way a stator that is wound to put out 28VAC at WOT would suddenly start producing 40VAC without some sort of stator failure... So, a typical pro tech in a working shop would stop right there and replace the stator before anything else.. Can always play around with the old parts on personal time (no employer gonna pay you 20 bucks an hour to play around with stuff that isn't gonna get billed on a repair ticket....) but I'd just about bet that machine was equipped with the stator brake stator and shoulda been 3 wires, but one got shorted, melted and burned and fused itself to the other... which would pretty much answer the question of how it suddenly started making 40VAC at WOT

[KE4AVB]

I reckon no one bother to read the SM [sections 8.12 and 8.13] as that green wire with 40 volts is the stator brake circuit. It must produce a minimum of 35 ac volts at 3400 rpm. Please try putting the diode in the black lead as it is the charge circuit. It also states that if when the black is disconnected with the diode still attach you should be getting 5 dc or more if the stator is working at 3400 rpm.

But since no one listens the new stator will fix the problem.

[bgsengine]

I reckon no one bother to read the SM [sections 8.12 and 8.13] as that green wire with 40 volts is the stator brake circuit. It must produce a minimum of 35 ac volts at 3400 rpm. Please try putting the diode in the black lead as it is the charge circuit. It also states that if when the black is disconnected with the diode still attach you should be getting 5 dc or more if the stator is working at 3400 rpm.

Says he did , 2 posts up - ---

With the green (and yellow that goes to the operator relay) not being used, I connected the diode to the black wire. At idle there was 12.0 volts across the battery terminal and at WOT it got to 12.7

So.. OK whole thread's left me confused what with all the talk of wire colors and the like - however... since he has green and black, and not a yellow, there *outta* be a yellow.. (if he isnt simply mistaking a painted/burnt insulation wire for being black) .. and either case, his WOT numbers are out of range ,so obviously needs a stator one way or another.. But seems to me if that stator was actually a 3 wire stator then one of the wires shorted out and burned/overheated resulting the 2 wires left, neither of which produces suitable VAC voltage for charging system use... but which would also solve the mystery of why there's only 2 wires in a stator brake system... and seems to me based on symptoms from the beginning, it'd make most sense if the charging system wire was the one that shorted (possibly just a high resistance connection leading to overheated diode.. or insulation rubbed through and shorted to ground .. or some such..) although it could as easily be the lighting system that shorted and welded itself to one of the other circuits... Lots of possibilities but the bottom line is the same - bad stator either way..