MTFCA Forum

I bought rebuilt coils about 5 years ago. There is no arcing across the points while running them on battery (6 volts dc).
I switch over to magneto and I have spark across the points. It looks like a roman candle. It disappears if I switch back to battery. What is going on with the coils and ought the coils not be run on magneto if they are arching like roman candles?
By the way, electricity and I are like "FM", friggin' magic -no moving parts. thanks for the help

The difference in tension.

6V DC (direct current by your battery) to 20V+ AC (alternating current by your Magneto).

I think there is nothing wrong with the coil or the magneto when it is running well on both.

Andre
Belgium

Paul ; what kind of Capacitors are there in the rebuild Coils ???

Toon

I don’t have the knowledge to help with this, but do you have a decent cell phone where you could do a quick movie showing them arcing [like a Roman candle}? I don’t know if you can post video here, but if you can’t, post it on YouTube and share the link. I’m curious to see this.

Much visible arcing at the points is usually an indication that the capacitor is failing or failed. If the capacitor is failing, you can sometimes also see pitting on the points. There still are some new coils being sold by the major vendors that use an incorrect capacitor which tends to fail quickly. There are also PLENTY of people building/re-building coils that THINK/talk like they know what they are doing, or just plainly doing a “cheap” job and think its just fine to use the .35 capacitor instead of the proper $2 one.

A coil with a cheap, incorrectly constructed capacitor will likely work just fine right out of the box, but begin to fail quite prematurely.

Thanks for everyone's input on the topic.
No, I do not know what the capacitor is in the coil as I bought them rebuilt.
I do not want to bring up the vendors name in all do respect.
I have a Simpson meter and would like to know the procedure to check the capacitor to see if it failing. How do I do this test?
Testing the capacitor will help me understand what is going on with the coils- thanks

http://www.mtfca.com/discus/messages/33 ... 1364507902
Ignore the spring cushion gap and stick with Fords recommendation.

Could it be that the magneto and battery positions have been swapped on your switch?

thanks for the coil diagram as I will check the points gap and inspect them from pitting.
Rebuilding a coil is out of the question due to fumes.
The wiring is correct on the ignition switch.
I will keep you informed of the coils.