DerbyDad03 wrote:

Assuming the FW key is the problem, how bad is it for the mower to run
like this? It's September in Upstate NY, so I only have a few more
mows before I'd be putting it up for the winter anyway. I'd just as
soon wait until the season's over before my first foray into small
engine repair.

Your choice. It'll take less time to fix than to buy a new one.