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cckemm

shorted alternator

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cckemm
working on the fire co's broadmoor II 6011. Long story short, fried an engine, stole one of our craftsman, 12 hp, everything the same, mounts, wires, cept newer with OHV, hooked up the wires and could tell instantly I had a dead short somewhere.:( After a little searching found that the alternator was the culprit, at this point just cut the wire to it so we could get back to mowing. Found also that the ignition switch no longer will ground out the magneto to shut the engine off, fixed this by putting on a toggle switch to a ground and that seems fine for the moment. Question is, why would have this shorted out? It worked fine on the other tractor. Don't wanna invest in a new one only to have it short right out again. Anything specific I should look for?? Chris

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Mel_W
Chris, You might want to remove the fly wheel for a look at the alt. windings and magnets, these can become clogged with dust and grass and will over heat than cause the windings to short. good luck, Mel

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HubbardRA
If I remember correctly, those engines only use two wires, an alternator wire and the ignition kill wire. Sounds like you have the two reversed. Even if the connectors plug in, these two may have been reversed between makes.

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cckemm
ok, did remove the flywheel and cleaned the thing up, thought I would find a burned spot but it looks brand new yet. No obvious short. The connectors were differant so they were both cut off am sure they were hooked up correctely from the start. This short showed up right away. So far as I can tell, alternator wired runs directly from the alternator back to the battery to the positive post. I did use the wiring diagram from simplicity, am sure that part of it was wrong because it did not match the main connector for one wire. Had traced everything from the begining to find the short in the first place. Could it be that the alternator wire isn't supposed to have 12 volts running to it? Chris

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HubbardRA
From my experience, the alternator wire always runs through the ignition switch, and never directly to the battery. That way it is unhooked with the ignition off. It will look like a short if connected to the battery without the engine running, because the battery will drain back through the alternator.

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cckemm
ok, the way it is originally wired, ties into the power wire to the ignition right at the main connector behind the dash. You are saying I should remove it from there and tie it into the power coming out of the ignition, I will try that. As far as diodes I didn't see any on the tractor or on the wiring diagram. where would I find the diode if there is one? For that matter I don't remember a voltage regulator either....hmmmmm. This is what happens when you have a plumber working on a tractor, lol, Mass Confusion...

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Agricola
Alternators produce AC and Batteries don't like that. The diodes need to be there somewhere. I would check the website of the engine you put in. They might have the diagrams that will tell you what you need to know.

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PatRarick
The diode is usually in the alternator wiring of the engine, right at the connector to the tractor wiring. It is usually covered by heat shrink tubing. The color of the wire(s) from the alternator will tell which alternator you have. If the engine was from a Craftsman, I would assume, and notice I said ASSUME, that you have either the 3 amp DC/5 amp AC (dual circuit alternator), OR the straight 3 amp DC+ alternator (DC only). If I am correct on this assumption, on the dual circuit alternator, you should have two wires coming from the alternator, a red one and a black one. The black wire has no diode. It produces 5 amps AC for the tractor lights. The red wire produces 3 amps for charging the battery. The diode should be in this wire to convert the AC power to DC. If you have the DC only alternator, there is only one red wire with a diode at the connector. Both systems are unregulated, so no regulator is needed. If the alternator has only one wire that is not red, OR if the wires are not red and black, post the wire color to find out which alternator you do have. Pat

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thedaddycat
OK Pat, now you have me confused on that one.... Is it 3 amps AC and & 5 amps DC or 5 amps AC and 3 amps DC? Which one is red and which one is black? Trying to figure out what you meant, my guess is red wire is 5 amps AC for lights and black wire(w/ diode) is 3 amps unregulated DC for battery charging. Could you please clarify it for me? Thanks

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HubbardRA
Recently put a Vanguard V-twin on a craftsman 12 OHV tractor. One wire for ignition kill and one wire for alternator connection on both engines. since alternator was shorted and ignition didn't shut off, sounds like the wires were reversed in your hookup.

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cckemm
Ok guys, now my head is spinning and I am seeing red and black wires in my dreams... Anyway, I had grabbed what was left of the wiring harness from the craftsman the other night and looked at it quick, have come to the conclusion that I must get a wiring diagram for the craftsman to figure out which connector went where. Everything was disconnected and just laying there in a pile. We are very busy at the fire co. right now getting ready for the annual Irish Festival that we have to pay the bills throughout the year, will probably be at least 3 weeks till I get the chance to sit down quietly with the two tractors and try to figure out where we went wrong. I am very glad for all the help you guys have given, Thanks Chris

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