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Wico PR trouble


Hello, I have a Wico PR that has intermittent spark, I'll either wont be able to start my engine or it will run great for an hour or so then it starts to act up, seemingly when it gets warm. I made sure the points cap is 7/64" as the instruction book says.

I have another PR that I put on the same engine to eliminate it being a non mag issue and it fires right back up again like no ones business and runs for hours while I saw.

I had the cover off and watched the inside of the mag while the engine died and was still coasting and tripping the mag. It was almost dark outside and noticed sparks jumping out of both coils at one trip or another, and a really bright one between the points at times.

I know this is a dumb question for those with magneto/electrical backround but what would be some possible issues causing this? bad coils? coil windings grounding out when the potting gets warm?

The coils seem to be original with tar potting or whatever they used, they are sitting on top of paper and the capacitor looks modern with plastic insulation on the wires while the coils have woven fabric. The wire that bridges the two coils has cracks in the insulation, not sure if this matters since it doesn't come into contact with the housing.

Thank you for any suggestions.



Sounds like bad coil/s to me. Arcing out once warm is a classic symton. Usually due to insulation breaking down and then the spark takes the shortest route to ground.
Start looking for a pair of coils at least. If you are going to rebuild this one for the small amount extra replace the condensor as well to ensure all is good.

Mitch Malcolm

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Your coils are junk a sure sign of a set of coils bad or on there way out is the glossy finish on the outside that is caused when the secondary windings are jumping between layers of windings . The currant is always looking for a path of less resistance to ground . :)


Thank you for the help fellas, Any online references to step by step disassembly of these? I know I could do it easy enough but don't know if there's a wrong way to do it that would effect the magnets in some way, any good suggestions for reputable sellers of coils? Also will it need to be recharged after the new coils are in? Thank you


I've not stripped a magneto as yet but one thing I have read on this forum is that the magnets need a keeper put on them before you remove them.
It is a very good thing you have done by asking first before getting into more trouble.
There are many people on this site that will be able to step you through the process. Sorry I am not one of them but do a search of the site to see if it has been covered before or if a wiko ek is similar.


Thank you, I have much to learn about them, I just love that you can leave them sit for months or years at a time and there's no battery to maintain.


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There's lots to know about the dandy Magneto... and I know many things about them, probably more than most.

the one thing I know for certain, is that a man who owns a magneto test station, and has the proper tools to recharge magnets, rewind coils, and test condensers to find the proper one, may seem a little expensive, but he's WORTH EVERY PENNY.

If you want it to be trouble-free, pack it up carefully, and send it to a locally-recommended Magneto Guru... you will NOT regret it.:wave: