Small Engines (Lawn Mowers, etc.): briggs ignition, darlington pair transistor, honda kawasaki

Question
Apparently briggs has a major ignition problem since I have about half a dozen of their ignition coils that either don't work at all or work for a few seconds and quit.  (I have a hobby fixing derelict mowers, but it doesn't pay to buy a $25 ignition part to fix an old mower so I'm wondering exactly what besides the coil windings are in these things that I can possibly get at Radio Shack and jerry rig them)  Thanks.  Clem

Answer
If you are talking about magnatron ignitions there is a transistor inside the sealed unit that acts like the points/condensor.

As for the Briggs units, how are you testing them?  I have only found a few defective coils, Briggs, Tecumseh, Kohler, Honda, Kawasaki or Phelon who make most of the coils for the other engine manufatures, that are actually bad.  A few have had no spark, one had weak spark and a couple would not advance.  The advancing coils usually use a darlington pair transistor.

Let me know how you are testing the coils.
Eric