6volt system question

[Josh_boro]

Finally got the 47 all back together after a complete rebuild and clutch replacement. Me and my mechanic friend ran into a electrical issue. When I bought the tractor it had a distributer. I bought a complete rebuilt magneto that was advertised as bench tested. However when we got it on and timed it did not produce enough spark to turn the engine over. We found out the previous owner had made it negative ground. We reversed the generator polarity and retired with no luck. For testing purposes we through the distributor on and timed it and the engine fired right up. My question is is the magneto faulty or is my electrical equipment not correct.
Is the relay on the generator correct for an original 6volt positive ground?

[KETCHAM]

A magneto is its own power source really.....don't even need a battery if you hand crank them to start.....Most old Cubs were Positive Ground....you can do them any way you want ,but the generator must be change to charge properly.......The kill switch grounds out the mag to stop the engine.

[Glen]

Hi,
The owner's manual, and the info I sent you in August have the answers to some of your questions.
Page 33 in the manual shows the Relay is the original part on top of the generator.
IH used them up to Cub serial number 115403, in 1950.
All Cubs up to mid 1964 were originally 6 volts, positive ground.

The positive or negative ground don't make any difference to the magneto, it isn't connected to battery power.
Don't connect battery power to a Cub magneto, it can damage it, they have said on here.
A magneto makes it's own power.
You need a different ignition switch than for a Battery Ignition unit.
The switch for the magneto has 1 post for a wire, and grounds the magneto to stop the engine.
TM Tractor at the bottom of the page has some, you can look at the pics.
The system should be positive ground for the charging system to work right.

The magneto may not make enough spark.
I would test the power of the spark the magneto is making.
The spark should jump a 1/4" gap. I sent you a PM.

[inairam]

did you change the switch? they are different but look the same

mag http://www.tmtractor.com/new/el/605fp.htm

battery http://www.tmtractor.com/new/el/446fp.htm

[Rick Spivey]

I suspect you may have had the magneto grounded; where did any wire off the stud on the magneto housing go? Hopefully you didn't hook the power wire that was on the distributor to that post, that can fry the internal parts. As stated above, a magneto has its own coil internally, and the stud on the outside is connected to ground, usually by a switch, in order to shut down the engine.

[Gary Dotson]

I repeat what Rick stated a bit ago, don’t ever apply battery current to a magneto!! That will fry the points faster than anything else that I’m aware of. If you made that mistake, have a look at the points. If you have not made that mistake, see if you mag will produce spark and run with the kill wire disconnected. That would indicate a problem with the switch circuit.