have you gone to the kohler website and downloaded the service manual for that engine? If not, strongly suggest you do so before going much further.

At what RPM are you running the engine when you read 12 VAC?
To test AC output of stator the RPM needs to be at 3,600 RPM (or the OEM governed RPM if less than 3,600).
You should get 28 VAC at 3,600 RPM

Are the stator wires the same color or different.
IF different, you don't have the charging system you think you do.

Mownie: All the way up (not sure of RPM's, but I think they are in that ballpark).

Bill: Stator has 2 white wires Part #237878-S

OK-
Just checking to make sure you didn't have the 3 AMP DC charge system with AC lighting.
That would have meant you were trying to measure AC from 1 lead and DC from the other.
Who knows what that would read on your meter.

From the Kohler service manual (which you can download from the Kohler website)

2. Remove connector from rectifier/regulator.
With engine running at 3600 RPM, measure AC voltage across stator leads using an AC voltmeter.
2. If voltage is 28 volts or more, stator is OK. Rectifier/regulator is faulty. Replace the rectifier-regulator.

If voltage is less than 28 volts, stator is probably faulty
and should be replaced. Test stator further using an
ohmmeter (Test 3).

3a. With engine stopped, measure the resistance across stator leads using an ohmmeter.
3a. If resistance is 0.064/0.2 ohms, the stator is OK.
If the resistance is infinity ohms, stator is open. Replace stator.

3b. With the engine stopped, measure the resistance from each stator lead to ground using an ohmmeter.
3b. If the resistance is infinity ohms (no continuity), the
stator is OK (not shorted to ground).
If resistance (or continuity) is measured, the stator leads
are shorted to ground. Replace stator.

Bill: I tested the stators. I used a HF digital meter and an older Micronta dial meter. With the dial meter, I touched the leads to each other and zeroed the dial. I then read from one of the white stator wires to the other. I tried it on all of the ohms settings, resetting the zero on each scale. Each of the scales swung the dial back to zero, if there was a difference in what I was reading thru the stator and with the leads just touching each other, I couldn't see it. I checked each of the stator wires to ground and this tested OK (no continuity).

With the digital meter I also tried all the settings. I read 0 on all scales until I got to the 200 scale. On this scale, I read .3 when touching the leads together, and .5 going thru the stator. Am I right in assuming that since I can't zero the meter, the actual reading would be the difference between the two?

I tested the other 2 stators and got identical readings for the resistance. I then tested a stator I have on another mower with an MV18 engine (same stator, different flywheel) and got the same readings. I didn't have time to test this stator for AC voltage while running but will do so tomorrow.

Could you speak to the possibility that this symptom could be present of the magnets were glued back out of order in the flywheel? My original flywheel had glued in magnets. It there a way to verify the polarity of these magnets?

Thanks, Ray

You have to use the lowest OHMs scale when reading such tiny amounts. Think of it as a %.

You also have to be careful of the way you hold the leads, since they can act as a radio antenna and affect the reading.

My gut feeling is that-
IF they matched up with a known good stator, you should be OK.

Just conjecture here (I'm currently stuck in a motel room) is that you MIGHT be able to test the orientation of the magnets.

POSSIBLY, if you had an extra magnet, you could check how it repels/attracts to the individual fly wheel magnets???????
That might be a meaningless test though. I'm simply thinking out loud here......
Maybe compare to a known good fly wheel to see if there is a trend
?

Well...I took a refrigerator magnet to my glued in flywheel. I can definitely tell a difference in them. Three of the magnets draw in the center, repel at the edge, and the other three repel at the center, and draw at the edge. The magnets are not alternating, but are three "innies, then three "outies". Tomorrow if the rain doesn't get me, I'm going to test the MV18 for the 28VAC, If I have that, I will pull the flywheel, check the magnet orientation, then put one of my other stators on the MV18 an reassemble. Thanks for your continued support.

I couldn't figure out how to post 2 photos on a message so this will be repeated with another photo. I took this off a Kohler MV18 that had some good readings, 30VAC across the stator wires and 14VDC at the battery when running WOT. Note the dirt in the flywheel. The real kicker is that NONE of these magnets are attached to the flywheel, when I took the flywheel off, 3 of the magnets stayed with the flywheel and 3 were stuck to the stator. I carefully removed them one at a time and put them in the flywheel. Note the position of the 3 refrigerator magnets stuck to the flywheel magnets.

This photo is of a flywheel removed from a Kohler CV20 troubleshooting a no charge condition. This flywheel was only reading 12VAC across the stator wires, with 3 different stators tried, and was not charging the battery at all. Note the "gorilla glue" holding the magnets on the flywheel. Also, notice the position of the refrigerator magnets, instead of alternating, they are stuck to 3 contiguous flywheel magnets.

I believe the PO reglued these magnets without paying attention to their position and (hopefully) this was the root of the no charge condition. I will verify that all my stators are good by substituting them in the MV18 after I get the MV18 flywheel glued up.

I'm also wondering if many of these Kohlers are out there running right now with the magnets loose. I think it might be possible that the magnets come unglued early on, but the problem doesn't show up until enough dirt packs in to dislodge them, which I understand also ends up damaging the stator.

Yep, here is a Kohler with dislodged magnets stuck to several of the stator coils. Kinda looks like a train wreck.

Luckily, my stator had not yet been damaged. One thing I "think" is true, is that it is very possible for these magnets to become unglued but stay on the flywheel, and your readings can still be OK. It's a disaster waiting to happen and could be very expensive. If the magnets come loose and are destroyed, you will probably need a new flywheel ($100 to $150) and if the stator is damaged, it's another $50. I think in the future I'll be pulling the flywheel on any older Kohler I get for myself. It's a good chance to look at this on your own schedule (before it breaks), Never-Sez the crankshaft where the flywheel bolts on, regap magnetos, etc.

Problem solved. It turns out that the ebay flywheel I bought ALSO had the magnets glued in improperly. The seller had no way of knowing that this was the case as he breaks down non running tractors to sell for parts. I was able to unglue the magnets in the original flywheel and reorient them. I'm getting strong readings now at the stator leads and at the battery. The ebay seller, joes_outdoor_power, has agreed to refund the price of the flywheel, even though I was long past the refund cutoff date. I really appreciate this gesture of business integrity!

Great-

It's good to know that the polarity can be checked too!

Don't you still have one out of synch?

Bill: I didn't explain the pics well enough. The pic in the last post with the white lettering is the ebay flywheel, and yes, it is out of synch. It could be made right by swapping the magnets at 2:30 and 5 oclock. The one I repaired was the original flywheel to the mower which had been gorilla glued. The ebay seller has graciously refunded my money and not asked for the flywheel to be shipped back. As an experiment, I may try to free these epoxied magnets with some heat and reposition.

BTW: I credit you with musing out the possibility of checking the polarity of these magnets. It also induced me to pull the flywheel off my MV18 to compare. These magnets were also unattached (although still charging) and could have caused a lot of damage if not caught. Thanks!

Checking the polarity was just some thinking out loud on my part.
YOU are the one that implemented the thought.

BOTH of us (and probably others) learned something here. Win-Win

Yes, thanks to you we now know the answer to the same dilemma which was pondered somewhat a couple of years back on this forum.

I am going through this with a Kohler CV22.

Pulled flywheel and found detached magnets (all of them), a couple broken, and a wrecked stator.

Has anyone found a place to purchase the magnets only, not a complete flywheel assembly?

As magnet replacement IS NOT "normally" done, there are no sources available for the typical consumer to obtain them.
Applications such as this are usually a "one off" process for the OEM builder (Kohler, in this case) and the magnets are proprietary to the OEM in the manufacture of the flywheel.
When the magnets simply detach and are not broken, there is a chance to re-attach them, but the polarity of each magnet MUST match the same orientation of the other magnets, and that requires a method to determine the polarity of all magnets concerned.
Your best hope, short of a NEW flywheel is to find a good used flywheel and stator.
Good luck.

Having same issues. Replaced regulater/rectifier & oem stator. Magnets were still attached & pulled on screwdriver (I didn't check for polarity as I wasn't aware it could be an issue) Getting 30 ACV from both white wires, .125 DCV from Batt + with harness connected. Engine seems to be able to charge enough to restart several times, even tho no charge shows on ammeter. When PTO is engaged, ammeter shows a significant discharge. No charging ever shows on ammeter. Kinda at a loss here. Any ideas other that to pull the flywheel again & check magnet polarity?

I was part of this original thread (scary how quickly it turned into a long time ago!) There are people on this forum who are expert on these engines. I just lucked into the possibility of the magnets being out of sync after going through a lot of the same steps you have. I know it is frustrating. I know that the magnets coming unglued is a common possibilty on an older engine if you aren't the original owner and don't know the history. I "know" that it is possible for the magnets to be unglued but the charging system can still work but is in danger or self destructing. It's easy enough to check the magnets when you pop the flywheel (and it should come off much easier this time ((you did neversez the taper when reassembling?)). I "think" it might be true that the system might charge a little if only 2 of the magnets are out of sync, but if they are 3 and 3 it won't charge at all. Please report back when you find the problem.

And...if you decide to buy a used flywheel from ebay, direct the seller to this thread and ask them to check prior to bidding or buying the flywheel. If they won't do this simple check based on the above pics, I wouldn't touch it.

Thank you. As much as I want to get this problem handled, unfortunately I' going to be out of commission for a few days (back surgery). I will reconnect when I can.