Small Engines (Lawn Mowers, etc.): No spark on Briggs 20hp riding mower, sparkplug wires, grounding wire

Question
It was running fine until this morning, then no spark.  Could it be the magneto or coil or something?

Background: The starter relay switch went out, so I have been hotwire-jumpstarting it.  My understanding is that there ought to be spark on this type of engine unless you kill it by grounding it.  I have disconnected what looks to be the grounding wire that runs into the engine, and still no spark.

If is the coil, how hard is it to replace?  I can't even see where the sparkplug wires lead to after they enter the engine assembly...

Thanks for your help!

Answer
Hi Stephen,

If the coil connections are good and the safety switch/es are working but still no spark, I would suspect a bad coil. You will need to remove the cooling shroud and maybe the flywheel to access the coil.

Let me know how you make out.
Michael