Ain't much going on in a Wico, or any other mag. I just fixed a Triumph with a Joe Hunt. It looked about the same as my John Deere. If you google Wico mags, you will see that they all look pretty similar at the sparky end. The engine-side and terminal count make them what they are. Points, condenser, coil, and a bit of wire. Just set the gap/dwell, and make sure that no wires are grounded out inside, or passing through the case. Open it up and have a look. You will see about all there is.
As wacky as it sounds, this tractor manual will provide insights: https://www.steinertractor.com/pdfs/ABC3723.pdf
When I put this kind of mag in anything that has a key, I put a stop button on the mag itself, at the screw terminal that passes through the case, as a safety backup. Then I run a normally-closed (when not powered) continuous duty relay between the ignition switch, controlled by the IGN lead. When the key is in the IGN or START position, the relay takes away the ground, ungrounding the mag, allowing it to make spark. Turning the key to OFF or ACC reapplies the ground, and kills the spark. This relay: HELLA 007794301 Cover with Weatherproof Mini ISO Relay has an N.C. (normally closed) and an N.O. (normally open) lead. You just cut off the lead you don't need. It is waterproof, when used with this harness/plug: HELLA H84709001 Pig-Tail Wire Harness for Mini ISO Weatherproof Relay Terminals 85 and 86 control the relay. Power one with the IGN wire. Ground the other. Ground 30, and connect 87a to the mag lead. Cut off 87 at at the plug, unless you want to use that to control something that needs to be running when the ignition is on (controlled by this ground).
Gimpy, I used to restore antique tractors, and The Brillman Company rocks!! They have such cool stuff. Mr. Brillman is a gentleman and super knowledgeable.
The Jalopy Journal
