Small Engines (Lawn Mowers, etc.): Scotts 1642 No Spark, model specifics, engine cranks

Question
QUESTION: The engine cranks. I am getting fuel and air but no spark on my mower. New spark plug and ignition coil were installed. I've checked the brake, seat and transmission safety switches and all seem to be working fine. I've checked all wiring for shorts, opens, grounds. Checked the fuse.

Model specifics are:

Product Identification Number GX1642S051746
Scotts 1642H
Datecode 032400

Kohler Command 16
Model CV16S
Spec Number 43526
Serial Number 3005600273

Thanks for your help,
John

ANSWER: Do you have the "Smart Spark" cdi ignition or the standard magneto ignition?

---------- FOLLOW-UP ----------

QUESTION: No it does not. Also, can you describe how to bypass/test the safety switches to make sure I'm doing that correctly. I also read the ignition switch could be the source of the problem. It grounds the wire on the 'M' terminal I believe to shut the engine off.

Thanks,
John

Answer
The simplest way to check the coil is to just unhook the kill wire from the coil.  Do this first to establish that the coil will fire.

After this, you have to check switches.  For the key switch, there should be no continuity from the kill wire to ground when the key is in the on position.  When doing this test, be certain to have the kill wire disconnected from the coil.  Sending voltage into the coil through the kill can ruin the coil.  Even the small amount of current from an ohmmeter can ruin a coil.  If there is continuity, then you have to isolate the key switch.  With a schematic you can see where there should be continuity in the on position and the off position.

The brake/clutch, neutral lockout, reverse mow and deck/pto switches, (If you have all these) can each be checked with a ohmmeter or a continuity light.  I don't have access to John Deere schematics and that would be a helpful thing to have.  But just by seeing if the switch is continuous and interrupted in the different positions will tell you if it's good or bad.  If it's continuous in both positions or interupted in both positions, then it's probably bad.  Thanks, PK.