Calling JohnT - Electrical Short Problem

RTR · Jul 7, 2012

I have a Cub Cadet 100 Lawn Mower that is giving me trouble. I just acquired a wiring diagram, and decided to test some things. I remember reading somewhere where you said a simple "spark test" is relevant to trace down a problem. My problem is that when you hook up the battery, I get a spark on the (-) post when the lead is touched to it. The (+) post is already hooked up when this happens.

With the (+) post hooked up, and the (-) post disconnected; I decided to test the connections at the VR. I first disconnected the (F) wire, then touched the (-) cable to the battery, still got a spark. I re-connected the (F) wire. Then I disconnected the (BATT) wire from the VR, and did the same test at the battery. NO SPARK. I reconnected the (BATT) wire. I then, tried the (L) wire at the VR. NO SPARK at the battery. I then re-connected the (L) wire at the VR.

WHAT DOES THIS TELL ME? WHAT DO I NEED TO DO FROM HERE?

Also, FWIW this tractor is equipped with the 12 volt "starter/generator" combo

Janicholson · Jul 7, 2012

Well ohn is in travel and merriment mode in the US west. I will however give an answer. The fact that it has a spark when the batt terminal is connected, and not when it is disconnected indicates that the Voltage relay cutout points are likely to be welded closed from either sticking from old age --Probable-- or from an incorrectly installed battery then started. Either can cause sticking. I would pull the cover off of it and see if the heavy set of contacts in it are closed. They should not be. Gently seperate them and use a finger nail file to dress them smooth, Then use a folded dollar bill to wipe them clean while pushing them together. If when you test the spark on the terminals it no longer does it with the batt terminal attached to the reg. start it and see if it works. if then sparks when shut off. (not good) I would replace the regulator. (american Made only) best of luck, Jim

RTR · Jul 7, 2012

(quoted from post at 01:29:45 07/08/12) Well ohn is in travel and merriment mode in the US west. I will however give an answer. The fact that it has a spark when the batt terminal is connected, and not when it is disconnected indicates that the Voltage relay cutout points are likely to be welded closed from either sticking from old age --Probable-- or from an incorrectly installed battery then started. Either can cause sticking. I would pull the cover off of it and see if the heavy set of contacts in it are closed. They should not be. Gently seperate them and use a finger nail file to dress them smooth, Then use a folded dollar bill to wipe them clean while pushing them together. If when you test the spark on the terminals it no longer does it with the batt terminal attached to the reg. start it and see if it works. if then sparks when shut off. (not good) I would replace the regulator. (american Made only) best of luck, Jim

Thank you so much Jim. I will go outside and do what you stated. However, I am having a hard time understanding this part of your post...[i:baab40b37a]If when you test the spark on the terminals it no longer does it with the batt terminal attached to the reg. start it and see if it works. if then sparks when shut off. (not good) I would replace the regulator. [/i:baab40b37a]

I also included a diagram of what I have done thus far.

Janicholson · Jul 7, 2012

The cleaning and separating of the points (if they were the cause of the discharge) will allow you to hook up all wires as normal and no sparks should happen as you brush the Batteries connection at the battery. When you test the spark on the Battery's terminal it no longer does it with the batt terminal attached to the reg If it still sparks let me know. Jim

RTR · Jul 7, 2012

(quoted from post at 01:39:26 07/08/12)

(quoted from post at 01:29:45 07/08/12) Well ohn is in travel and merriment mode in the US west. I will however give an answer. The fact that it has a spark when the batt terminal is connected, and not when it is disconnected indicates that the Voltage relay cutout points are likely to be welded closed from either sticking from old age --Probable-- or from an incorrectly installed battery then started. Either can cause sticking. I would pull the cover off of it and see if the heavy set of contacts in it are closed. They should not be. Gently seperate them and use a finger nail file to dress them smooth, Then use a folded dollar bill to wipe them clean while pushing them together. If when you test the spark on the terminals it no longer does it with the batt terminal attached to the reg. start it and see if it works. if then sparks when shut off. (not good) I would replace the regulator. (american Made only) best of luck, Jim

Click to expand...

Well, well.....guess what I found. There was 2 wires twisted together behind the dash and I noticed that the key switch was not hooked up at all. I assumed those wires to go to the switch since no other wires were unhooked. I put on new terminal ends, hooked up the switch, and low and behold the spark is gone!!! The Cub Cadet has the original style key switch and didn't come with a key. I didn't think about it not coming with a key and therefore they left it wired together. I have several copies of original keys, so by hooking it back up it is functional now.

I poured some gas in the tank and fired over on the starter for several turns, choked it, fired it over again, and it started right up. It runs excellent, with the exception of just quitting randomly after being ran for around 5-10 minutes. When it dies, it starts right back up. It revs up and down perfectly and idles perfectly. I'm not too concerned at this point. The coil felt warm, but not hot. I'm sure that is normal. I also took my multimeter and put the leads on the battery posts with it running. It read 12.45 volts, so I guess that is a good sign that the generator is charging.

Janicholson · Jul 7, 2012

Good evaluation. If the battery is down some 12.45 might be OK, but 13.8 to 14.4 is more like it. Fully charged 12v battery should be at 12.6 volts when charged and nothing attached or "on" Jim

RTR · Jul 7, 2012

With that said, I will run it for around 30 minutes tomorrow and re-check the battery with it running. If it isn't more that 12.50 volts; is it safe to say that the genny isn't charging?

Janicholson · Jul 7, 2012

Yes. I would charge the battery with an external charger, then read its voltage. If it is 12.6 (should be a bit more just off the charger) I would read it again when running 3/4 throttle. If mroe than 13 and if you do not use the headlights, it might be OK. Be sure your meter is reading accurately, test a car or truck battery to be sure it is close to correct. Jim

Calling JohnT - Electrical Short Problem

RTR

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Janicholson

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RTR

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Janicholson

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RTR

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RTR

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