There is another trick that one of your uncles or perhaps your father knew about when it came.

Mix old gas with new gas. The old gasoline mixed with the new gas, will then lower an entire tank’s combustion ability to such a level, that it is no longer a concern. Unleaded gasoline at a few years of age is no longer properly gasoline and won't combust inside an internal combustion engine of the design in any automobile, motorcycle or. Old and new gas should not be mixed for a variety of reasons, the major ones are;

If you only have a half of tank of old gas in. Even 10 year old would probably fire up ok, at least on fuel injected engines where the system is more or less closed to. Can you use 4 year old gas?

1 year old fuel will be fine if the can is properly closed. However, gas that is more than two month old is generally ok to. The old gas degrades over time it should not be added because it has already lost it's combustibility.

It is not okay to mix old gas with new gas in a lawn mower. Mixing old gas with new gas is normally not an issue for most vehicles. Old gas and gas reconditioning yes and no.

I am going to do a minor service on it and the gas is probably 2 maybe 2 1/2 years old.