Beecrofter wrote:

...Classic symptoms of a bad ignition coil...


A hot ignition coil can open up, but that would cause the engine to stop
when it heated up, not a starting problem. However, if there is
insufficient air circulation in the engine compartment, the ignition
coil can get hotter when the engine is stopped. How long does the mower
have to sit before it starts again? 5 min? 30 min? 6 hours?

Vapor lock? When the engine is hot take off the air cleaner and put
about a tablespoon of gas into the carburetor and see if the engine
catches.