Eduskator

As I initially said, fill it up completely to dilute the crappy fuel and drive it. Put some fuel treatment in it. It's not like you put half a tank of bad fuel.

moparado

I typically use old gas to burn leaves, fallen tree branches and old paper work (better than shredding).

Speaking of contaminated and/or old stale gas, i think i've got a similar problem with my old IH Farmall tractor which i haven't started in a few years.
Last time i used it brush mowing, it start sputtering when going up a hill and never stopped sputtering.
Been resting ever since.
One more project on the list.

tropical36

So, you're all saying that there's no fuel treatment out there, other than for water, that will make stale gas, good enough for the mower?

MattXLT

No, get rid of the gas and get new stuff. For small engines, like my mower, snowblower, ATV, and snowmobiles, I ONLY use non-ethanol non-oxygenated PREMIUM. And after a year of it sitting in the red can, I dump it in my truck where it dilutes with 30+ gallons of gas and gets burned up the following week through normal driving.

Eduskator

Might be a water bubble stuck in the carb... Or a dirty carb. Only one way to find

Just don't see why the guy would need to empty his fuel tank for 1gallon (3% of tank's capacity) of bad fuel. Once filled completely with fresh fuel, it will get diluted and errrrrthing will be all right. I once put 5gallons of bad fuel in my Civic, filled it up with fresh fuel when I realized it was sputtering, ran it (it did run rough a little, but nothing intense). It was OK after.