Farmall H 12 volt conversion

Shahn · Jul 5, 2008

I have a Farmall H that had a 6 volt ignition system and I am trying to convert it to a 12 volt ignition system. I believe I have all of the wiring and harware in place but it won't start. Spark is coming out of the magneto but there is no spark at the spark plugs. Can someone tell me where the problem may be?

CNKS · Jul 5, 2008

Did it fire before you changed the wiring? A magneto is a self contained ignition system and is completely independent of 6 or 12 volts. The battery voltage goes ONLY to the starter, lights, and generator, not the coil on the mag.

Shahn · Jul 5, 2008

Yes, the tractor did start and run before I changed everything to 12 volts.

old · Jul 5, 2008

Did you by chance make the mistake of hooking up 12 volts to the shut off terminal on the mag?? If you did then you probably fried the mag. But if your still getting spark from the mag but not getting to the plugs I would say you have a bad rotor or cap or the cap is wet or cracked
Hobby farm

Shahn · Jul 5, 2008

Possibly. My instructions said to run a wire from the ballast resistor to the + terminal of a coil, then from the - side of the coil to the distributor. Since I have a mag (instead of a coil), I ran the wire from the resistor to the a post on the side of the mag. Is this not correct?

old · Jul 5, 2008

If you hooked the wire up like that you stand a 95% chance you fired the mag since its does not use battery voltage to work. So no doing that is not correct and is probably what has caused you no run problem

Shahn · Jul 5, 2008

How can I correct my wiring problem? I have a wire that goes from the ignition shut off switch to the resistor. If the wire does not go from the resistor to the mag, where should it go?

tn terry t · Jul 5, 2008

(quoted from post at 16:14:20 07/05/08) How can I correct my wiring problem? I have a wire that goes from the ignition shut off switch to the resistor. If the wire does not go from the resistor to the mag, where should it go?

url]http://s101.photobucket.com/albums/m46/farmallbob/Farmall%20Tractor%20Wiring%20Diagrams/[/url] go here and look for a conversion with the mag if you havent already burnt things up that post on the mag should have no connection with the positive side of the battery no resistors or any thing matter of fact it will run with no wire hooked to it

Shahn · Jul 5, 2008

I unhooked the wire that I had going from the resistor to the mag and now the tractor starts and runs. I see now that the shut off terminal on the mag needs to be grounded to shut off the motor. My instructions said to run a wire from the ignition switch to the resistor, from the resistor to the + side of the coil, then from the - side of the coil to the distributor. Since I have a mag, should this step be eliminated? If so, where should the resistor go?

tn terry t · Jul 5, 2008

your instructions are wrong!!! thats for a battery ignition you got luck this time you need to go to the website i posted earlier it will show the proper way to wire your tractor the "proper" switch for your mag has only one wire conection the other conection is thru the body of the switch NO RESISTOR IS NEEDED

old · Jul 5, 2008

With a mag you don't need the resister or the wire that goes to it. A mag is a self contained ignition system which is not hooked in any way to the battery or alternator. Do so you risk burning up the mag and you got lucky that you did not burn out the coil in the mag which would have cost you %40 plus to replace

Wayne in MN · Jul 5, 2008

Tape it back into the wiring harness; it should not be used. Disconnect the wire in the switch box also since it is only to be used with a battery-coil type ignition.

Farmall H 12 volt conversion

Shahn

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CNKS

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Shahn

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old

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Shahn

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old

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Shahn

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tn terry t

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Shahn

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tn terry t

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old

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Wayne in MN

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