Small Engines (Lawn Mowers, etc.): B&S model 40777 22HP Type0124E5, briggs and stratton, bridge rectifier

Question
This engine has two coils and a diode on each kill wire to the kill circuit in each coil. When the ignition switch is turned off, only one coil stops firing allowing the motor to run on one cylinder until the safety solenoid on the carb stops gas flow. I have swapped the diodes around, replaced both of them removed them completely(motor won't start like that). If I put two seperate wires on the two coils, with the insulation off the other end of wire, crank the motor and touch both wires to gnd, motor dies instantly. Briggs and stratton techs were totally confused as to what the problem can be.I would appreciate your help.

Answer
I might not be of more help.  But to add my two cents I would say that each coil has to be grounded to kill the engine.  The diodes in the wire change AC to DC voltage and prevents flow in both directions.  The diodes should be checked with a continuity meter continuity should go one way and not the other.  If you have one going both ways replace it you can't jump around.  The way the spark is created is when the field breaks down current goes through the step up through the spark plug wire to the spark plug and jumps the gap somehow that is not happening on one of the coils.  If you swap the coils and problem goes to the other side replaced the coil if it doesn't it could be equipment related because I am confident you have a battery ignition.  If you have a schematic it will show where the wire grows to ground I would suggest going backwards to a regulator/rectifier or bridge rectifier to see if they need to be replaced there again these are diodes just directing electricity it has to be were they killed circuit splits out a schematic all I can say is traced the circuit.  I hope this helps good luck.