On Wed, 21 Jun 2017 12:54:47 -0700 (PDT), "Terry S."
wrote:

I left my lawnmower out in a thunderstorm two days ago and now it won't start.
It's a Craftsman "Self Propelled" push model with a Honda engine.
Any ideas on how I could get it running again?


Craftsman = Sears don't wait too long .. Sears is bankrupt.

Electric start ?

Safety interlocks issue ?

Wet grass clogged ? preventing a proper spin for starting ?

place next 50 wild guesses here

Good luck.
Honda small engines are famous for reliability and starting.
... whether a lawn mower, portable generator, portable sawmill ;
etc

John T.