[Larzfromarz]

Actually while the points are closed a magnetic field is being created in the coil. When the points open the magnetic field in primary coil collapses and induces and current in the secondary coil (remember its really a transformer) that creates the spark at the plug. Honestly with a 50/50 chance, if it won't start (and everything else is good), flip the thing and see if it will.


So for general knowledge- When a coil "shorts" internally is is usually due to overheating and the varnish that insulates the wire melts and internal contact is made either in the primary or secondary winding itself (reducing the ability to build the proper magnetic field) or the contact is between the primary and secondary coils thus completely defeating and chance of a current being induced into the secondary resulting in either very poor or no spark. The coil, thru magnetic induction (the electrical theory behind transformers) takes our battery voltage that we supply to the system and transforms or "steps up" the voltage to around 20-30,000 volts for spark at the plug.
Transformers can step up voltage or step down voltage. An example of a step down voltage is the little "wall wart" or transformer that we charge all of our gadgets on (cell phones etc). Takes "wall voltage" 110v AC approx and transforms, steps down the voltage to something you can use (6-12 vdc). This is why they say not to leave these things plugged in. They use energy all of the time and dissipate that energy as heat or dollars into the air.