Fuel stabilizer keeps gas fresh for 12 months. Shelf life is 2 years after opened. No harm if older, just not as effective. Don't use if very dark red or brown color.

 

Just replaced my 23 year old Honda lawnmower with a new one. The new one is much quieter and the mulching is much better. I spoke to the salesman and he said that they were flying off the shelves. He didn't know that production was going to stop in September.

 

When it comes to tough outdoor engines I'm a Kohler guy. I have two one 12.5 horse and the other a twin at 22 hp.
Last year I had to pull the carb and clean it because it sat for 3 years and the float got filled with yuck.
I didn't do anything special just disassembly and reassembly less the yuck, oil change, basic tuneup, Fired right up.

oh and that is a 30 year old machine,

 

I had a Kohler motor on my go-cart when I was a kid. If I remember right it had originally been used to run a highway construction sign. It ran well never had any issues.