Small Engines (Lawn Mowers, etc.): B&S 17 hp riding mower, no spark, safety switches, system theory

Question
Ref:  model  311707
     Type   0132-E1
     Code   980127ze    

I can't get spark on my 17hp B&S engine.  At first I couldn't even get it to turn over.  I replaced all 3 safety switches and the coil (magneto). It now turns over beautifully. I gaped the magneto at .007.  No spark.  I later read on the internet the proper gap is .020.  I've tried them both with no success.  It's a pretty straight forward system, but I'm stumped.  I did order a flywheel puller to see if there is anything under the flywheel that could be creating problems, but I'm not very hopeful.  

Any suggestions would be greatly appreciated.  I can't afford another mower.

Thanks,

John

Answer
Nothing under the flywheel to cause the problem.

Good article on the ignition:

http://www.briggsandstratton.com/us/en/support/faqs/ignition-system-theory-and-t

The easiest way to check the coil is to dis-connect any wires connected to the coil...should only be one small wire.  Check for spark.  If you have spark the coil is good.   

Is the coil mounted correctly?  Not upside down is it?

Eric