Usually it’s the fuel diffuser in the carb, if you are mechanically minded. It’s the tube the main jet screws into in the bowl. It gets its micro holes blocked and then starts to idle eratically, eventually not starting.
Last year I cleaned the carb out, cleaned the exhaust baffle as that can affect the choke efficiency, and adjusted all the belts and cables so it now goes in reverse again, we’ll it did last year, I am hoping the gremlins haven’t got back in it this year.
The spark plug is the easiest and best place to start though, you might get lucky