312-8 with K301S Possibly not charging

[TC10284 111]

I've got a 312-8 with K301S engine. I don't have a model number for the tractor itself. 

Anyway, I've had issues with this keeping it running when it's cold. I work through that by playing with the top jet on the carb. Eventually it evens out after going in and out some...
However today...I had it running for about 10min to haul a trailer to the basement to carry boxes to the road for pickup. I let it idle at the basement and when I came back out, it was off. Not a big deal I guess. Except I tried to turn it over and it did nothing. Voltmeter showed 8-9v. Just previously, it was around 12v. 

So bad battery you'd think, right? 

EDIT: The battery definitely tested bad with a load tester just now. 

 

However...

I connected up a Litium ion jumper pack. Voltmeter went up to 12v. Got it running again. Disconnect battery pack. Engine starts to die. Connect battery pack back up and it picks back up again. 

Finally disconnect it completely and right before it dies, engine suddenly picked up on it's own. Voltmeter still showing ~8-9v. Got another WH from the shed and let the 312-8 idle the whole time I was hauling boxes. 

Took a voltmeter and connected to the battery. Opened throttle all the way. Still showed ~9v. Regulator showed 9v (if I remember). Connected to + and - terminal on coil and saw really odd voltage. On my voltmeter, it would go from around 9v, flash over 250v, go back down, and repeat. Very quickly. Got no clue what was going on there. 

 

Anyway, does it seem like it's not charging? Where should I start testing? I have less experience with Kohler engines - probably because I have to maintain the Onan's more often. Sorry to open that can of worms, but that's just how it is for me.  

Edited June 19, 2019 by TC10284

[gwest_ca-(File Mod) 11,187]

Do your headlamps work with the engine not running? This will help us determine what charging system you have. One system uses power directly from the engine to power the lights and the faster the engine runs the brighter the lights.

 

You can not test a charging system with a bad battery in the circuit. The results defy logic and are unpredictable. The jumping around of the voltage could be stray EMF if using a digital voltmeter. Analog meters are not as sensitive to this.

Get a good charged battery in the tractor and clean up all the connection points including the grounds. Oxidation at the terminals causes resistance and that also affects the test results.

 

Garry

[TC10284 111]

5 hours ago, gwest_ca said:

Do your headlamps work with the engine not running? This will help us determine what charging system you have. One system uses power directly from the engine to power the lights and the faster the engine runs the brighter the lights.

 

You can not test a charging system with a bad battery in the circuit. The results defy logic and are unpredictable. The jumping around of the voltage could be stray EMF if using a digital voltmeter. Analog meters are not as sensitive to this.

Get a good charged battery in the tractor and clean up all the connection points including the grounds. Oxidation at the terminals causes resistance and that also affects the test results.

 

Garry

 

I'll get a new battery and try it that way. I found a manual for a K301 and will run through some of the tests they show. But you're right, I have no idea what charging system it has after reading through the tests. 3, 10, 15, etc amp. 

Right now I don't think the headlights work even when it's running. I'll have to test that again and check the fuses. Been rainy and messy outside today. 

The engine spec # is 47812. 

 

See if you can view this pic: 

https://photos.google.com/share/AF1QipOcgOAV28w5CcOefSY86naBo5pzQPGw5J6yQQou2XvKH89CKhSgAQQzcg53_-HAYQ?key=Vmpia0d6OEpPRGhVNUluUU1zU0xROFFxS2RCTExn

 

[gwest_ca-(File Mod) 11,187]

Here is your tractor. It does have the 3 amp charging system and the only place the 47812 spec was used. Click on the fuzzy picture.

Garry

[TC10284 111]

I got a new battery and connected it up. Started and ran fine. No issues. Ran better than before. 

I found this service manual and on page 80/81 there are tests you can do to see if it is charging. 

https://kohlerpower.com/en/engines/product/k301

 

I checked the voltage of the battery after I left it on my battery maintainer for a few days. In the mower with switch off, I saw 12.69V. With the engine running at 3000rpm I saw 12.59V. According to the manual, the charging system tests fine at 12.5v or greater. 

 

On test 2, it says to remove the battery charging lead and test voltage output. Does this mean the positive cable connecting to the battery? Is it OK to remove it when it is running? 

Edited June 23, 2019 by TC10284

[TC10284 111]

Just wanted to follow up on this to see if anyone else had any advice. 

[pfrederi 18,205]

The battery charger can create a surface charge.  That fools other chargers and voltmeters into thinking the battery is fully charged when it is not. the 12.69 you saw initially after charging was probably that.  I would say you are good to go.  If you want to do step 2 you have to disconnect  the three wire plug coming from the engine.  You will have to put a jumper from the battery to the coil start it run it and test the output from the charge wire. You will have to disconnect your coil jumper to stop the engine.  But why bother??

[953 nut 56,836]

[TC10284 111]

Sorry to resurrect a very old thread, but this guy is definitely not charging. 

I have used this tractor off and on semi-regularly since then. Battery has held a charge. Went to use it to mow, battery at 9.3v. At WOT, the battery leads stay at 9.3v. After about 30-45min of mowing part of the front yard, battery is at 9.35v. 

 

Also at WOT, I get right at 14v from the bottom two wire leads of the three wire connector. I get 14v on both sides of the two lower wires of the main three wire connector that goes to the tractor wiring harness. 

I get around 6v at idle from these two wires. 

 

Where is the voltage regulator rectifier on a k301? 

Or:

What can I check next to determine why it's not charging? 

Edited October 14, 2021 by TC10284

[Gregor 4,847]

Do you know the year of your tractor, or the serial number? Or do you have a spec number on the K301?

[TC10284 111]

13 minutes ago, Gregor said:

Do you know the year of your tractor, or the serial number? Or do you have a spec number on the K301?

 

The tractor model and serial in front of the seat is worn off. My guess is 1986.

 

Hers a pic of the engine 

https://photos.app.goo.gl/hRcwtBhDoCAJf8vZ7

Edited October 14, 2021 by TC10284

[Gregor 4,847]

1 hour ago, TC10284 said:

14v from the bottom two wire leads of the three wire connector. I get 14v on both sides of the two lower wires of the main three wire connector that goes to the tractor wiring harness. 

This has me a bit confused. Where does the 3 wire connector go to?

[TC10284 111]

2 minutes ago, Gregor said:

This has me a bit confused. Where does the 3 wire connector go to?

 

Two wires come from behind the engine shroud that goes to the main engine connector. One wire comes from the main connector to the coil. I'll get a pic soon. 

[Gregor 4,847]

This is a rectifier. Do you have this anywhere on your tractor or motor ? I have never worked on anything this new, I am only going by wiring diagrams and pics,

Edited October 14, 2021 by Gregor

[TC10284 111]

4 minutes ago, Gregor said:

This is a rectifier. Do you have this anywhere on your tractor or motor ? I have never worked on anything this new, I am only going by wiring diagrams and pics,

 

That's what I've been looking for. 

Unless it's under the shroud, I don't see it. 

[Gregor 4,847]

It is not under the shroud. It may be located on the tractor itself.

1 hour ago, TC10284 said:

I get right at 14v from the bottom two wire leads of the three wire connector.

Can you tell the color of these wires?

1 hour ago, TC10284 said:

I get 14v on both sides of the two lower wires of the main three wire connector

Are you talking about the same connector?

 

Sorry for all the ???. Like I said, never worked on anything this new

[TC10284 111]

2 minutes ago, Gregor said:

It is not under the shroud. It may be located on the tractor itself.

Can you tell the color of these wires?

Are you talking about the same connector?

 

Sorry for all the ???. Like I said, never worked on anything this new

 

https://photos.app.goo.gl/915XT4FMa2wJi9Sm9

[TC10284 111]

 I'm looking at another 312-8 with k301 and it has the exact same setup. 

https://photos.app.goo.gl/ig9JmLB5qL71dC9n8

Edited October 14, 2021 by TC10284

[Gregor 4,847]

 There should be 2 wires coming from under the shroud. You should get 13+ AC volts from these wires. Unless it is unlike anything I have worked on yet.  Something, somewhere, on that tractor, has to change that 14 VAC to DC to charge the battery,

This pic show a diode/rectifier on the motor. Maybe there is something under the shroud. Are you measuring AC or DC voltage? But then this pic also show magneto ignition, and you don't have that.

[gwest_ca-(File Mod) 11,187]

Headlamps only work when the engine is running? If so it is a 3 amp unregulated but rectified system to charge the battery. One wire at the connector will have a diode in it that you should feel through the tape covering it. Look for a bugle about 1/4" in diameter x 3/8" long.

The other wire comes straight from the stator directly to the headlamps.

 

[TC10284 111]

58 minutes ago, Gregor said:

 There should be 2 wires coming from under the shroud. You should get 13+ AC volts from these wires. Unless it is unlike anything I have worked on yet.  Something, somewhere, on that tractor, has to change that 14 VAC to DC to charge the battery,

This pic show a diode/rectifier on the motor. Maybe there is something under the shroud. Are you measuring AC or DC voltage? But then this pic also show magneto ignition, and you don't have that.

 

Yep, this is what I was referring to above. I got 13V+ AC. Almost 14V AC on both sides of those two wires. 

[TC10284 111]

37 minutes ago, gwest_ca said:

Headlamps only work when the engine is running? If so it is a 3 amp unregulated but rectified system to charge the battery. One wire at the connector will have a diode in it that you should feel through the tape covering it. Look for a bugle about 1/4" in diameter x 3/8" long.

The other wire comes straight from the stator directly to the headlamps.

 

 

Yes, lights only work when engine running. 

Yep, bingo. Found it:

https://photos.app.goo.gl/gG48MBKiY1qqc3cj7

 

I think my next step is to make sure to fully charge that battery, test it with a load tester, recharge it, and then proceed with Step 1 in the troubleshooting guide above. 

 

So question on Step 2 - "Disconnect the charging lead from the battery". I take that to mean the following:

With engine running, put a jumper wire from from positive on battery to positive on coil?

Then disconnect the main three wire connector from the tractor wiring harness. Then proceed to Step 2 test. 
 

 

[953 nut 56,836]

1 hour ago, TC10284 said:

Hers a pic of the engine

Please attach your photos to your post, attempted to open your photo but needed a password.

5 minutes ago, TC10284 said:

I got 13V+ AC. Almost 14V AC on both sides of those two wires.

The output side of the diode should be 14 volts DC with the engine running.

[Tuneup 1,433]

Those systems are not designed to provide adequate charging to a battery that is in its death throes. Did I get that word right? They are designed to keep a healthy, charged battery healthy. It's amazing that the coil fires adequately at 9 VDC. My typical NAPA coil decided to kill my old C-120 when the trash battery (which had easily started it earlier) reached 8.5 VDC. That is with a healthy regulator. These 1/2 rectified systems won't supply the current. That battery is toast. Get a healthy one, charge it and then diagnose the electrical. It might just be perfectly fine.

[Gregor 4,847]

I've never seen anything like this. Learn something new everyday.

 

Just curious, do the lights operate on ACV?

Edited October 15, 2021 by Gregor