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How Long Does Gas Last? (And How to Extend Its Life Span)

How Long Does Gas Last? (And How to Extend Its Life Span)
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With winter seasons and such a year can go by with gas just sitting in the gas can. If you put the same gas in the tank it will still burn but is it really good gas?

Gas can be store up to half a year in a normal can but there is really no solid answer on a timeline for this due to many variables.

Not knowing how much oxygen gets in and out of the tank. This will dramatically effect how long gas will last. With gas being exposed to oxygen the hydrocarbons can change. This will result in gas becoming gummy as further discussed below.

Another factor that really affects how long gas will last is the seasons. As the weather constantly changes from hot to cool to frozen this change in weather will allow moisture to get into the tank and deplete many additives.

Not only will the moisture deplete many additives in gas but it will also make the gas less flammable. Once the gas is no longer ignitable you could be running to even more costly engine repairs.

The one thing that can be confirmed is that potency of gas will decline over time.

Old Gas in Cars

Not only will the potency decline over time but if the old gas is left in a motor it could also cause damage to your carburetor. When gas gets old it tends to get “gummy.”

When this happens the carburetor will most likely tend to start having issues.

How Does a Carburetor Work?

Inside a carburetor is what’s called a float. The float works like inside a toilet. As the gas is used the float drops allowing more gas to enter the carburetor and as the carburetor fills with old gas the float rises stopping more gas from entering.

If the gas is old it will cause with the float to stick and stop working properly or the pin to freeze up. If this occurs the old gas will have caused you motor failing to start due to the carburetor no longer allowing gas to flow through it.

Gas Stabilizer

Gas Stabilizer

If you know winter is upon your or you are going on vacation it is best to prevent old gas. This can be done with a product called Sta-Bil which is a fuel stabilizer.

Putting Sta-Bil in your gas can will allow your gas to last up to 2 years and it is quick, easy and cheap to do.

How Much Gas Stabilizer per Gallon?

Simply mix Sta-Bil with your gas with the following stabilizer per gallon ratios.

  • 1 Gallon Gas – 1/2 an Ounce Stabilizer
  • 2.5 Gallons of Gas – 1 Ounce Stabilizer
  • 5 Gallons of Gas – 2 Ounce Stabilizer
  • 10 Gallons of Gas – 4 Ounce Stabilizer
  • 15 Gallons of Gas – 6 Ounce Stabilizer
  • 20 Gallons of Gas – 8 Ounce Stabilizer
  • 25 Gallons of Gas – 10 Ounce Stabilizer
  • 40 Gallons of Gas – 16 Ounce Stabilizer
  • 80 Gallons of Gas – 32 Ounce Stabilizer
  • 160 Gallons of Gas – 64 Ounce Stabilizer
  • 320 Gallons of Gas – 1 Gallon
  • 640 Gallons of Gas – 2 Gallons

In Summary

How long does gas last? With the proper treatment gas can last up to two years. If you know you are leaving town, winter is upon you or you are simply storing any kind of motor with gas in it simply add some Sta-Bil to it to ensure the gas get the longest life span possible.

If you catch it in time and the carburetor isn’t gummed up the best thing you can do is add as much fresh or new gas you can. This will mix with the old gas making it more flammable and allow you to burn through the old gas.