Even 10 year old would probably fire up ok, at least on fuel injected engines where the system is more or less closed to.

Mix old gas with new gas. However, gas that is more than two month old is generally ok to. When you add new gas to a tank that has old gas in it, the two ages of gas will mix and still be usable for your vehicle. Old gas and gas reconditioning yes and no.

It is not okay to mix old gas with new gas in a lawn mower. 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;

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. I am going to do a minor service on it and the gas is probably 2 maybe 2 1/2 years old. If you only have a half of tank of old gas in.

Gas begins losing its combustible properties and leaves behind a varnish as soon as 30 days after purchase. The old gas degrades over time it should not be added because it has already lost it's combustibility. I figured i'd use it's electric fuel pump and pump the old gas into a container.

Mixing old gas with new gas is normally not an issue for most vehicles.