Huh. Go figure. Nice catch, nice repair.

There is a contributing factor. Gasoline, or what passes now for gasoline. It's no where near as toxic as it once was (I'm sure you remember the days as gas as a shop solvent) but it degrades and fouls quickly. I'd suggest if the Covid enforced inactivity continues that you use an additive occasionally in your gas. I like "Sea Foam", but there are several to choose from. It'll tend to keep things cleaner during times of inactivity (and active. That gunk builds up and it is STICKY).

Glad you got your problem solved quick and easy instead of 'slow and dirty'.