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Wico magneto

R

Revredneck

Member
I have a 2 cylinder Wisconsin engine with a Wico magneto on it. I have taken it apart and cleaned everything, including the points. The coil checks okay with an ohmmeter and I replaced the condenser. The problem is that it has no fire. I talked to a guy who rebuilds magnetos at the Old Threshers Reunion this weekend, and he said my magneto should never have a problem with the magnets, even though the magnet feels pretty weak to me. I think he really wanted me to spend $175 for him to rebuild it for me (No thanks).
I have re-arranged the internal wiring of the mag so that I can put voltage to it externally, and the spark is very hot (temporary rigged setup, about 6 volts input). Here"s my question: What should the input voltage be in order to keep from burning the coil? I figure a simple universal ignition resistor may not limit the current enough. Anybody have a "knowledgeable" recommendation? I have some knowledge of Ohm"s law, and can figure the voltage/current for the unit, so a fairly technical answer doesn"t scare me too much.
Good Luck and God Bless,
Tommy
 
1.) You can't make a MEANINGFUL test of a mag's coil with an Ohmmeter.

2.) I DOUBT the mag's coil will last any length of time with you pouring battery voltage into it. That's AGAINST all conventional wisdom.

3.) If you WANT to make a distributor out of it, use a standard "round-can" automotive ignition coil of the appropriate voltage. Remove the connections from the internal coil, and connect the points and condensor to the external coil and the coil's high-tension lead to the lead connecting to the "carbon button" contacting the rotor.

If it uses NO rotor and a 2-output coil, you can use a coil for an Onan or Kohler "twin" that has two high tension leads.
 
If you put a external battery ignition coil wired separate just to points and condenser fine you just converted it to a battery distributor. If like Bob said you added battery voltage to the original magneto coil congratulations you just FRIED IT ! Magnetos were designed to make their own fire not needing any kind of external battery voltage ever. That terminal on the side was only for a grounding switch to stop it. Adding battery voltage to a magneto can also ruin the magnet so no surprise if it's weaker now. If no switch or resistor to reduce voltage lucky it didn't fry off the points and condenser. Wisconsin magnetos are a dime a dozen at online auctions plenty around for parts or find another working one.
 
Mag coils cost about 80.00 points 20.00 condensers 20.00 ,rotors 15.00 Wico C has 2 caps at 30.00.If you have applied 6 volts the coil is roasted.Perfect example of why some if not all jobs should be left to people who know what they are doing.A mag can damage its coil if it sparks with out a load such as a spark plug gap.A simple mag repair can use a 100.00 worth of parts easy.
 
How are you checking spark? Those coils spark from one button to the other, not to ground like a normal mag. Does the impulse snap? Are you turning it over clockwise or ccw? Explain how you rewired it inside when you put battery current in it. Or did you use another coil?
 
If the magnet is weak, it can be recharged by wrapping a coil of wire around it and using a transformer like from a toy train, or a small battery charger. I've recharged many magneto magnets this way. An actual magnet charger that has a machined surface that fits the contour of the magnet works best. The coil of wire will make the magnet plenty strong. Just have to remove it from the housing though.
 
You may have cooked the mag's coil by using battery voltage. You can convert it easily with an auto coil and disconnect the mag's coil. Here's a tractor's mag that has been converted to a distributor. Touching those magnets with a flatblade screwdriver should attract that screwdriver with a lot of effort. Hal
2z3zbpv.jpg
 
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