Small Engines (Lawn Mowers, etc.): b&s 18 hp no spark, changing spark plugs, primary coil

Question
hi eric asked a question last week about not getting spark. you asked for the model # .. i tried to write back but it seems you are very hard to get a hold of.. your questions are maxed out.but i caught you tonight..after reading other q&a on this and different hobbytalk sites i am sure i found the problem ..so i ordered a new coil...did every thing from bypassing the safety switches to checking the coil gap,changing spark plugs still no spark..my question before i put the new coil on, the yellow wire that connects to the small black wire coming from the coil which i guess is the wire the turns off the motor when you turn the key off. with a test light i have power coming from the yellow wire when the key is in the off position.. no power when the key is on.is this correct? can you explain how that works? shouldnt it just  ground the coil out to stop the motor? i think this website is very cool that people can talk to experts like you and get info that helps do it yourselfers get the job done ..I THANK YOU FOR YOUR TIME.. p.s. is there a easier way to get a hold of you? being on the west coast i dont have a chance being the first two questions before you are maxed out..

model#422707
type#1510-01
code#92010812

THANKS  

Answer
To make sure the coil is bad, remove the top engine sheet metal to access the coil.  Dis-connect the small wire connected to the coil.  Remove spark plugs and check for spark while cranking the engine.  If there is no spark then the coil is bad.

You are correct about the coil...the ignition key switch grounds the primary coil winding when you turn the key off.

Take you volt meter and check the small wire you dis-connected from the coil.  It should NOT have any voltage on it at all.

Let me know what you find.  We may have to trace the problem backwards if the coil ground wire has voltage on it.  12 volts on the coil ground wire will difinitely burn-up the coil.

Eric