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Craftsman - Kohler Mo# 917.271030. wires and connector connected to the voltage regulator burnt

#1

biplob827

biplob827

Please help!
I have an old riding mower (bought used recently). While mowing, the engine turned off and it wouldn't click or crank when I turned the key. I noticed the carburetor was leaking gas and the 30 Amp fuse was blown, so I replaced them both. I was able to start the mower, but right away I smelled something burning and I noticed the 2 yellow wire connected to the voltage regulator was really hot and melted! Please help me with some suggestions on how I can resolve this. I can't even find the wiring and connectors parts number on the manual that I found online! Please help! Thank you.

Please click on the link for pictures of the problem:

photos.app.goo.gl

Lawn Mower problem

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photos.app.goo.gl photos.app.goo.gl


#2

I

ILENGINE

The only thing that I can figure that those two wires off of the regulator with the special connector with the burnt end would feed the headlights. Nothing else in the system would even be remotely AC powered. I would be checking to make sure the headlight wires didn't get close to the muffler, melt and then short out.


#3

Scrubcadet10

Scrubcadet10

ILENGINE said:
The only thing that I can figure that those two wires off of the regulator with the special connector with the burnt end would feed the headlights. Nothing else in the system would even be remotely AC powered. I would be checking to make sure the headlight wires didn't get close to the muffler, melt and then short out.
Click to expand...
I've seen it a time or two.


#4

biplob827

biplob827

Scrubcadet10 said:
I've seen it a time or two.Thank you, I will check the headlights wiring. But the headlights never worked on it through!
Click to expand...


#5

Hammermechanicman

Hammermechanicman

I have seen this a few times. The problem is the terminals get loose and create a high resistance connection and then gets hot and melts the connector. I fix them by getting new crimp faston connectors that fit the lugs on the voltage regulator. Cut off the old connector and crimp on new terminals.


#6

sgkent

sgkent

The damaged connector may have been a problem waiting to happen, but another problem may be present too. If I had to guess, the connector was corroded and as stated that caused resistance and heat. The fuse blowing might say something else went on too, so I would still look to make sure nothing has chaffed against the frame or muffler. If one looks at that wire, one side of it is not overheated but the other connection side is. That points to a bad connection on that one side of the wire. However that may have been the weakest point so when the system overloaded and popped the fuse, that connector sort of acted as a fuse too and melted. Basically a fuse is a conductor that has a bit of resistance in it, so if too much power passes thru it, it heats up and melts before the wires do. But a dirty connection can also act as a fuse and burn up. So, effectively whatever caused the overload may have damaged both the fuse and connector.


#7

biplob827

biplob827

Kindly advise if I should replace regulator, wiring and connectors? If so, what would be the parts number? I can't find it in the manual!


#8

Hammermechanicman

Hammermechanicman

I am not sure you will find a kohler part number for the white Molex connector and the pins plus you need a special crimp tool for the pins. Star tech the forum parts magician may have them. I would delete the connectors and just use faston terminals to the voltage regulator. You may have a other problem with excessive current draw from the looks of the relay. May want to see what it is controlling and see what is causing the excessi e current draw.fn02800-01-thumbnail-1080x1080-70.jpg


#9

StarTech

StarTech

First the wiring doesn't the model number given and I see no reason for 40+vac for headlamps. Something definitely not right.

Voltage Regulator 25 403 37-S

Amp Mate n Lok Plug 350779-1
Amp Mate n Lok Connector Housing 926682-1

20-14 ga Terminals
Amp Mate n Lok Pin 926883-1-CT (cut strip of 100)
Amp Mate n Lok Socket 350536-7 (cut strip of 100)

Voltage Terminal Housing Aptiv 02977646
Relay Terminal Housing Aptiv 12010832
Terminals used Aptiv 2935867 (16-14 ga)

Note above terminals will need an open barrel crimper to crimp them so these will fit into the plugs and housings.





#10

I

ILENGINE

StarTech said:
First the wiring doesn't the model number given and I see no reason for 40+vac for headlamps. Something definitely not right.

Voltage Regulator 25 403 37-S

Amp Mate n Lok Plug 350779-1
Amp Mate n Lok Connector Housing 926682-1

20-14 ga Terminals
Amp Mate n Lok Pin 926883-1-CT (cut strip of 100)
Amp Mate n Lok Socket 350536-7 (cut strip of 100)

Voltage Terminal Housing Aptiv 02977646
Relay Terminal Housing Aptiv 12010832
Terminals used Aptiv 2935867 (16-14 ga)

Note above terminals will need an open barrel crimper to crimp them so these will fit into the plugs and housings.



Click to expand...

the whole thing is strange. And I can't think of anything other than headlights that would work with AC And like you I can't see the 40+ for headlights unless they are running them parallel and not in series so half wave AC to each headlight.


#11

H

HughDaHand

It's probably a stater brake designed stop the engine quicker when powered off. They were fairly common on these kohler equipped craftsmans of this era.


#12

H

HughDaHand

Here is a schematic that includes a startor brake. The model number you listed doesn't seem to include one in it's schematic, maybe there was an engine or wiring harness swap in its past.
Screenshot_20220509_222657.png


#13

Scrubcadet10

Scrubcadet10

ILENGINE said:
The only thing that I can figure that those two wires off of the regulator with the special connector with the burnt end would feed the headlights. Nothing else in the system would even be remotely AC powered. I would be checking to make sure the headlight wires didn't get close to the muffler, melt and then short out.
Click to expand...
IL,did you see the last picture in his photos? It looks like those two yellow wires go into a relay....


#14

I

ILENGINE

Scrubcadet10 said:
IL,did you see the last picture in his photos? It looks like those two yellow wires go into a relay....
Click to expand...
I did but I don't see a reason for them to be wired to a relay. While would you connect AC to a relay. And if they were connected to the same relay would create a dead short back to the stator. I was just thinking they were a casualty to a backfeed on the ground side of the relays. There is a major short someplace in that system. And I wouldn't be surprised if the stator is also cooked.


#15

sgkent

sgkent

the regulator has a 15V dc output on that schematic. On the red wire going to a relay.


#16

StarTech

StarTech

HughDaHand said:
Here is a schematic that includes a startor brake. The model number you listed doesn't seem to include one in it's schematic, maybe there was an engine or wiring harness swap in its past.
View attachment 60449
Click to expand...
Now that maybe the case. So many DIYer out there that changes from original setups. But this schematic makes better sense than the in the operator manual for the model the OP gave. He may have a stator that is also damage by it running shorted for so long with a shorted braking circuit.

It is the first time I seen a setup like this on a Kohler engine. Most usually have a separate braking winding on the stator.

Here is what Kohler did on the CV461-26504 stator PN 12 085 09-S in the above schematic.
1652176248585.png


#17

Scrubcadet10

Scrubcadet10

ILENGINE said:
I did but I don't see a reason for them to be wired to a relay. While would you connect AC to a relay. And if they were connected to the same relay would create a dead short back to the stator. I was just thinking they were a casualty to a backfeed on the ground side of the relays. There is a major short someplace in that system. And I wouldn't be surprised if the stator is also cooked.
Click to expand...
True.


#18

Hammermechanicman

Hammermechanicman

If they are using the stator as an engine brake i would just delete the relay and the extra wiring to the regulator. I have seen some really over complicated (stupid) wiring on mowers. If that schematic is right i will put it in that category.


#19

I

ILENGINE

Hammermechanicman said:
If they are using the stator as an engine brake i would just delete the relay and the extra wiring to the regulator. I have seen some really over complicated (stupid) wiring on mowers. If that schematic is right i will put it in that category.
Click to expand...
Very true, it would be gone in my book with that issue. Looks like a perfect way to cook a stator on engine shutdown.


#20

H

HughDaHand

This style stator brake was most likely rushed out to meet new safety standards, stopping the blades faster when the safety switches cut the engine. The OP is now finding out why newer version of this have their own winding on the stator for the brake. I'm betting the relay failed while he was mowing causing the stator bake to engage and stall the engine.


#21

B

bertsmobile1

ILENGINE said:
I did but I don't see a reason for them to be wired to a relay. While would you connect AC to a relay. And if they were connected to the same relay would create a dead short back to the stator. I was just thinking they were a casualty to a backfeed on the ground side of the relays. There is a major short someplace in that system. And I wouldn't be surprised if the stator is also cooked.
Click to expand...
Well they are on 87 & 87A so would be NC thus shorting out the stator when the ignition is turned off
Not the best way to electronically brake an engine


#22

biplob827

biplob827

Thank you all for your kind help. So, the 2 yellow wires that are connected to the AC line, are they for headlights? Can I eliminate them? The headlight never worked anyway. I tried to trace the 2 yellow wires, they go in a relay (1 of 3 relays), and then I lost it! The wires from 1 relay go to the second and then the third!


#23

sgkent

sgkent

Try to find the correct wiring diagram for your mower and your questions will be better answered. Good luck.


#24

StarTech

StarTech

biplob827 said:
Thank you all for your kind help. So, the 2 yellow wires that are connected to the AC line, are they for headlights? Can I eliminate them? The headlight never worked anyway. I tried to trace the 2 yellow wires, they go in a relay (1 of 3 relays), and then I lost it! The wires from 1 relay go to the second and then the third!
Click to expand...
No they are for the engine braking system per diagram in post #12. It appears the system failed or was wired wrong and the engine braking was applied while the engine was running normally and not stopping thus massive amounts current was being generated.


#25

I

ILENGINE

biplob827 said:
Thank you all for your kind help. So, the 2 yellow wires that are connected to the AC line, are they for headlights? Can I eliminate them? The headlight never worked anyway. I tried to trace the 2 yellow wires, they go in a relay (1 of 3 relays), and then I lost it! The wires from 1 relay go to the second and then the third!
Click to expand...
And to answer your second question. Yes they can be eliminated.


#26

StarTech

StarTech

Thanks IL. The coffee hasn't kick in yet here. Beside I just had to rewire my keyboard USB cable. Shorted out as I was posting. It time for a new keyboard anyway as half of the letters are missing.


#27

G

Gord Baker

I believe you have a direct short somewhere . A fuse would not allow that type of damage if it was in that circuit.
High resistance somewhere or melted insulation. Follow each wire, replace any overheated connedtions and clean all mating surfaces that wires connect to. Good Luck.


#28

S

stephen165

I have to tell you to run don’t walk from this model I had it since it was new with that exact engine and it was constant electrical problems from the third year forward.. I can tell you is that there was a diode instead of a rectifier to turn ac to dc (it was the cheap way to do it) and that diode used to overheat and fry the wiring, If I recall correctly, the right way to do it is to convert the diode into a rectifier which is what it should’ve been in the first place for an engine this size. What I did was I extended the wire and put the uninsulated diode on top of the pull start inlet air screen and the cool air being pulled over it solved the problem but it was a rig. I remember that somehow also that engine threw the plastic governor gear in the bottom end andI had to take it apart and put it back in place. I can tell you this before I figured out the diode thing I must have went through forty 30 amp fuses and freid a bunch of wire before figuring it out…


#29

biplob827

biplob827

Again, thank you all for your kind advice. I found the correct schematic diagram, and it looks like there is no purpose for those 2 yellow wires. Kindly correct me if I am wrong. I eliminated the 2 yellow wires and the mower is running fine and the battery is charging.

Attachments





#30

StarTech

StarTech

Yes that the schematic for the model posted, just not how your mower wiring is setup. Yours was setup with an engine braking system so wiring diagram in post #12 would be the correct one to go by.


#31

S

stephen165

Good news! But keep an eye on the wrapped diode when it overheats it fries all different color wires if you try to over fuse it


#32

biplob827

biplob827

Update: So, after I eliminated the 2 yellow wires, the mower was starting and charging fine. I was able to ride it as well. But, as soon as I engaged the mower, the fuse blew! Then I put a new fuse, same result, it blew again as soon as I engaged the mower to cut grass. I can drive the mower, but cant engage the cutter! Please advise. Should I connect the yellow wires back the way it was? Thank you.


#33

I

ILENGINE

Leave the wires disconnect and determine what is shorting out the pto.. The overload of the yellow wires could of damaged and fused the wires going to the electric clutch.


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