How Long is Gas Good for Lawn Mower: Expert Advice

Need to know how long you can store gas for your lawn mower? With our extensive knowledge in lawn mower maintenance, we’re here to provide you with the definitive answer to your question.

How Long is Gas Good in a Lawnmower:

Gasoline can go bad within 1-3 months. Use a fuel stabilizer when storing gas to extend fuel life. Harmful gas can clog filters and damage fuel lines and carburetors. Drain old gas and add fresh fuel with a stabilizer. Consult a mechanic if engine problems persist after draining old gas.

Now that you know that gasoline cannot be stored in the fuel tank forever, you should also go through the details of why and how it goes bad after a certain period and the adverse effects bad gasoline has.

Why and How Does Gasoline Go Bad?

Gasoline can go wrong because of several chemical phenomena, e.g., evaporation or oxidation. The chances of these phenomena happening and the speed at which they proceed depend on gasoline contents. The details of how and why gas goes wrong because of these phenomena are given below.

● Evaporation:

The proper gasoline combustion in the combustion chamber of your mower’s engine depends on its chemical and physical properties. The correct proportions of its contents, weights, etc., play a vital role in combustion.

Even a slight change in these properties can adversely affect the combustion process. The evaporation of a pure substance and a mixture are different because their contents evaporate at other times and rates depending on their nature.

– The Process of Evaporation in a Mixture

For instance, if a mixture of two liquids, A, B, and A, were more volatile, it would evaporate first. The same things happen with gasoline that has other chemicals blended in it. The more volatile components disappear first.

The bad thing is that the mixture’s lightest components evaporate first, making gasoline heavier. As said earlier, a change in gas properties affects combustion. The more severe gasoline does not combust appropriately. This means that the engine will still run but not correctly.

● Oxidation:

Oxidation is the chemical process that occurs when chemicals react and combine with oxygen to produce new compounds called oxides. For example, rusting is a form of oxidation in the presence of moisture. Oxidation of gasoline is an even more severe issue than evaporation.

Fuel oxidation occurs as hydrocarbons in the fuel react with oxygen to produce new compounds. This makes a semi-solid called gum, creating deposits all over the fuel system and clogging filters and lines.

Gum makes the affected components malfunction, causing the mower not to run smoothly or not even start at all. Gum can also affect the carburetor very severely. Gummed-up carburetors won’t work unless fixed, and fixing them is expensive.

● Ethanol:

These days, gasoline takes much less time to expire than it did some years ago. This is because of the introduction of ethanol in the fuel. The Environment Protection Agency implemented the use of ethanol in the fuel in an attempt to make the fuel more environmentally friendly.

Ethanol is a type of alcohol that is derived from corn. Nowadays, ethanol takes up to ten percent of the 87-octane gasoline. Adding up to ten percent ethanol made fueling environmentally friendly and cost-effective but created a problem for small gasoline engines. Remember that the gasoline engine of your lawnmower is also a “small” engine.

The problem with ethanol is that it draws moisture from the air as it sits in the garage or shed tank. This moisture waters down the gasoline. An engine with this watered gasoline in its combustion chamber will not start, stutter, or die during the operation.

– The Problem with Small Engines

The problem with small engines such as those in lawnmowers is that they are used only briefly after several days. After use, leftover gas stays in the tank until the subsequent use. This causes exponential growth in the chances of your gasoline reaching its expiration date.

Once the gasoline expires, it causes all sorts of problems for the components of your mower’s fuel system. Fuel lines, carburetors, and seals deteriorate. A varnish buildup caused by expired gasoline can cause tiny fuel pores to clog.

Clogging of the fuel ports will make it impossible, or at least almost impossible, to start the engine. Gasoline with ethanol can last for a maximum period of 3 months. However, we advise you to consume it before that period. Using fresh fuel is very important for the health of your machines.

● Water:

Water can build up in the tank you use for storing gas. Water buildup occurs due to condensation because of temperature changes throughout storage. Water buildup degrades the gas and makes the proper combustion of gas impossible.

Reusing Old Gas:

Although reusing old fuel is not a good practice, it can be done in some cases, but the gas must be treated first to make it less harmful. Old gas can be reconditioned through nylon and cotton cloth, adding fresh gasoline in a specific ratio.

This can make the old gasoline reusable, but reusing it is not a good practice, and we don’t recommend it. Another essential thing to remember regarding reconditioning and reusing old gas is that it can be done only for engines with carburetors and not fuel injection systems.

Furthermore, this process requires special care and can’t be done by everyone. Seek the help of a mechanic if you wish to reuse old gas by reconditioning it.

Bad Fuel: Using a Fuel Stabilizer

If you intend to store fuel in a tank for more than 30 days, you should mix it with a fuel stabilizer. Using the right fuel stabilizer and integrating it with the fuel in the correct ratio will allow your fuel to sit in a tank without the dangers of pitting and gumming for more extended periods than if no stabilizer is used.

The ratio of fuel stabilizer to gasoline depends on the stabilizer brand. For correct info in this regard, you should contact the stabilizer’s manufacturer that you intend to use. An important thing to remember is that the fuel stabilizer ratio depends on the stabilizer brand and not on the mower’s model or brand.

For example, some brands recommend an ounce of stabilizer for a gallon of gasoline, while others suggest an ounce for 2.5 gallons. Another essential thing to note is that the fuel stabilizer works only with fresh fuel. You cannot add a stabilizer to old gasoline and expect it to refresh.

Fixing a Mower Affected by Bad Gas:

If your engine isn’t starting right or causing trouble because you are using old fuel, stop immediately and siphon out the old gas. Any built-up residue in the engine needs to be removed, too.

If your engine runs for some seconds and then dies even after adding fresh fuel, the carburetor has been clogged by the thick varnish-like substance that builds up after volatile components in the fuel have evaporated. Use a carburetor cleaner to clean the carburetor, and use fresh fuel with a stabilizer added to it.

For more details on servicing your mower affected by harmful gas, consult the manufacturer or a professional mechanic.

Remarks:

Gasoline can be stored only for a specific time before it goes bad. How long can gas be stored? Well, as little as 30 days under certain conditions. Gasoline goes wrong because of additives that evaporate or oxidize, degrading the fuel. This is a condition known as gas that has deteriorated.

When this happens, it is terrible for your engine. Our advice is to always use fresh fuel, preferably with a stabilizer added to it in the correct ratio. A popular choice is Sta-Bil. This is especially important if you suspect that the gas has gone wrong. One way to check is by looking at the color. The color of fresh gasoline is clear, and any discoloration could be a sign of lousy gasoline.

When storing your mower for the winter, drain and dispose of the fuel instead of storing it with fuel in the container. Any fuel left in the mower over the winter could be lousy gas when you use it again. Cleaning your mower regularly and maintaining it properly is also essential.