340 turns over, got spark, won’t fire and run

How old is the fuel?
Had one here recent that we could not get to run until we replaced a half a tank of one year old fuel.
The fuel we get now is junk, if smells the least bit funny is gone bad. You can dump as much snake oil in it as you want it won't help.
Good luck, let us know how you do.
It’s got a full tank of year old gas.