Burned through coil wire.

[havoc1482]

So I literally burned the core of the external wire that runs from the top cap of the magneto to the distributor cap. How is this even possible? At first I noticed an arc jumping from the rubber sleeve that slips over the coil cover to the mag just below it. Then moments later the tractor stopped running and the wire was completely burned out internally at the ends. There was some carbon on the rotor end, but every other wire was fine. I just replaced the coil.

In the video you can only see the stronger arcing, but in fact there is a constant arc in the location. Its too faint for the camera to pick up on.

[tst]

are you using metal plug wires, not silicone type?

[havoc1482]

I'm not sure. I bought these wires because they were the same my boss used on his Cub. They have straight plug connections instead of a 90* elbow that would get caught up on the side of the cylinder head.

They were from Napa and the "wire" inside looks like a blue-greenish hair instead of a metal wire.

Note that I bought these wires months ago, I didn't just put them on.

[tst]

that is a silicone wire, not made for magneto, you have to use copper plug wires, throw them away

[John *.?-!.* cub owner]

I believe you just got a demonstration of why we all recommend using plain copper wires on magnetos.

[havoc1482]

Weird, never knew about this. Curious, why don't they work well with mags?

Also, what do you guy recommend and where to buy? I'd like to get the straight plug boot again. I wouldn't mind making my own I suppose.

[havoc1482]

WOW! I just put copper cored wires on the Super A and WHAT A FREAKIN' DIFFERENCE! It idles so smoothly and starts up easy. I guess I must have been getting really bad and inconsistent spark from those old wires.

[Denny Clayton]

WOW! I just put copper cored wires on the Super A and WHAT A FREAKIN' DIFFERENCE! It idles so smoothly and starts up easy. I guess I must have been getting really bad and inconsistent spark from those old wires.

I believe you just got a demonstration of why we all recommend using plain copper wires on magnetos.

[Matt Kirsch]

If I'm not mistaken the spark from a magneto is far and away "hotter" as in higher voltage, than anything you can get out of a battery ignition, even these high-performance racing systems. The silicone wires aren't rated to that high of a voltage, which is why they burn through.