How To Tell if My Lawn Mower Gas is Still Good

When your lawn mower sits for 4-6 months, that is a question that comes to mind before you pour what could be bad gas into your lawn mower.

Today’s gasoline begins to deteriorate in 90 days and its condition only worsens from there. If you put fuel stabilizer in the gasoline, then it will be good for us to 5 years! Gasoline is expensive, so you don’t want to waste it.

To test your gasoline, you can smell it first and if it has a sour odor to it, more than likely it is bad. You can also pour a small sample into a glass jar. If it doesn’t appear to be very clear with a slight yellowish tint, then it is going bad. As gasoline ages, it begins to turn darker in color. Sitting in a carburetor, it will begin to evaporate and leave a crusty residue behind that will plug up the idle and main jets of that carburetor.

If your gas can doesn’t have a cap on the nozzle, it can also attract moisture because of the ethanol in the gas. Ethanol is a form of alcohol and that will pull the moisture and be absorbed into the gasoline. This is why it is so important for the use of fuel stabilizers today.

What Kind of Gas Should I Put in My Lawn Mower?

Your lawn mower is usually has a 4-cycle engine on it. Some older models had a 2-cycle engine but there are not many of those left so we won’t worry about them.

A 4-cycle engine is designed to work on unleaded gasoline. There are normally 3 or 4 different octane levels of gasoline available. 85, 87, 90 and 93 are very common throughout the country. A lot of people are under the misconception that if they buy 93 octane, their engine will run better when actually the opposite will occur. A higher octane fuel is designed for a higher compression engine. Most lawn mower engines are on the lower scale of compression.

Find the lowest octane rating such as 85 and that will work fine. You could also use non-ethanol fuel to help prevent your carburetor from experiencing problems. Ethanol has been a terrible additive for gasoline engines and especially carburetor engines. Ethanol is alcohol and it attracts moisture and this adds water to your fuel. Water is never good to have in fuel.

Do not put E-85 in your lawn mower gas tank or any other alternative fuels. They will destroy your engine over time. So if you just stick with regular old pump gas, your lawn mower will run like it should.