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Lawn Mower Gas: What to Use

Lawn mowers are important outdoor tools that are necessary for all lawn owners and landscapers, and most lawnmowers make use of a combustion engine. Due to this, the lawn mower would require some amount of gasoline before it can run. To know the kind of fuel that is required by your particular lawn mower, you should check the owner’s manual; the one that comes with your lawn mower. Depending on the type of lawn mower, some may require gasoline with a higher octane while others may not. There are even some lawn mowers that use diesel fuel instead.

Lawn mower gas, what to use:

Most lawnmowers can use normal gas, but check if the ethanol content is not to high, and make sure that the octane is at least 87, but preferable higher. If you have a 2-Cycle engine you have to mix a 2-Cycle Oil and make the correct fuel mixture. Check the manual how many oil is needed.

Having a lawn mower machine always comes with the responsibility of carrying out regular maintenance and care in order to keep it up and running. This regular maintenance task also includes knowing how fuel can affect the performance of your mower, and how important it is to use the right fuel in ensuring that the mower remains in a good working condition all year round.  It is important that you do not make the mistake of assuming that all gas are the same or that you know the exact type that works for your lawn mower. Using the wrong type of gas would only cause damage to your mower’s engine, and in some cases, you might even void your warranty. Do you want to know the right type of gas to use for your mower? In this article, you will be provided with all that you need to know in order to get the most out of your fuel and use your mower for a long time.

What Gas Should I Use?

The right kind of gas for your lawn mower doesn’t necessarily have to be expensive or out of the ordinary. You can easily get a good quality fuel for your mower just by considering these requirements:

● Must be clean and fresh

This is important because fuel begins to deteriorate as little as 30 days

● Octane:

Should have a minimum of 87 octane/87 AKI (91 RON).

● High altitude:

For high altitude operations, gasoline with up to 10% ethanol (gasohol) or up to 15% MTBE (methyl tertiary butyl ether), is acceptable. You can find them at some fuel stations even. However, the E15 product is not recommended for use in small engines. Small engines have low compression ratios, which simply means that they won’t get any benefit from the gas unlike those with higher octane rating. In fact, some premium fuels can make starting your equipment difficult.

● Canned fuel:

A canned fuel product can also work just fine. Canned fuel combine unleaded ethanol-free gasoline with a fuel stabilizer so as to prolong the life of the fuel.

● RVP rating:

The RVP rating of fuel is also as important as the octane rating, so take note. That’s why you’ll see gasoline refineries raising and lowering fuel RVP ratings seasonally just to account for the differences in temperature. Simply note that summer Fuel = low RVP rating while Winter Fuel = high RVP rating.

● Ethanol content

To reduce unnecessary problems during usage, purchase fuel with the least amount of ethanol content as possible. Most gas stations sell an ‘E-10’ gas which contains about 10% ethanol; this is suitable and safe for your lawn mower equipment. Ensure that you avoid any ‘E-15’ gasoline as 15% ethanol gases will only cause damage to smaller engines.

Another good option may be to go for a pre-mixed/ engineered fuel that does not contain any ethanol. You will easily find a wide variety of these fuels on the market as they are premixed and ready to use with your 2-cycle or 4-cycle engines. Below are simple ways to mix oil in a small engine.

  • 2 Stroke Cycle Spark Ignited Engines: Always mix high quality, 2-cycle lawn mower oil, at a gas to oil ratio of 50:1.
  • 4 Stroke Cycle Spark Ignited Engines: Do not mix oil in gasoline, or modify the engine to run on alternate fuels. This will only damage the engine components and void the warranty.

Why Does Gas Go Bad?

Some people may not know this, but gasoline is only good for about 30 days. Once it exceeds this time frame, the volatile compounds present in the gasoline will begin to evaporate. Evaporation will take place regardless of whether the gas is in the lawn mower or in a gas can. When the fuel evaporates, it forms a brown gummy deposit that becomes extremely viscous. With time, the deposit will turn into a hard varnish that is capable of clogging the fuel lines and carburetors. Once this occurs, you may begin to notice some telltale signs of poor engine performance such as:

  • Lack of power
  • Engine surge, and
  • Difficulty starting

Why Should I Be Careful with Ethanol?

Most gasoline, especially those found in the Midwest, contains up to 10% ethanol. Modern lawn mower engines are designed to run on fuel with up to 10% ethanol. The moment you start dealing with fuel containing more than 15%  ethanol (also known as E15 fuel), you are at the risk of getting into trouble and ruining your mower engine. E15 fuel or any fuel with high ethanol percentage will absorb water from the atmosphere, causing a significant amount of corrosion in the fuel system. Water in the fuel tank can also cause clogging of the fuel system, and this can cause starting problems as well as costly repairs. One way to prevent water from accumulating in the fuel tank and causing damage is by adding a fuel stabilizer to the engine, at the beginning and end of each season, and even to fuel left in the gas after usage.

Mixing a 2-Cycle Oil and Fuel Mixture

To determine whether your small engine is a 2-cycle or 4-cycle, take note of the number and type of fill ports on the engine. If your mower engine has only one fill port for both the oil and gas, then just know that you have a 2-cycle engine. Simply pour the 2-Cycle oil into an empty gasoline can then add one gallon of fresh gasoline into the can. You don’t need to apply any additional pressure or agitation to this mixture. If you plan on storing the mixture for more than 30 days, add a fuel stabilizer to the gasoline before mixing it together, so as to help increase its shelf life.

Remember to label the gas container that holds the 2-cycle oil mixture as this would help prevent accidentally using it in other engines. In addition, never use gasoline with an ethanol content higher than 10%. As stated earlier, ethanol attracts moisture when exposed, and this can cause corrosion or clogging of the fuel system if used. It can even result in damage to your engine’s carburetor.

How to Put Gas in your Lawn Mower

Step 1. Locate the gas tank:

Locate the gas tank on your lawn mower. For some lawn mowers, however, their gas tanks are usually covered up, as with the rest of the engine. Search for the gasoline receptacle which is often covered with a black cap, alongside a symbol signifying gasoline on the top.

Step 2. Remove the gas cap.

Most lawn mowers use a threaded cap that can be easily twisted right off of the top. However, you’ll find some other common types of gas caps such as the lock caps that require a key to open, or a cap that is usually fastened down at the bottom by a keyed locking mechanism. This can be simply opened by turning it until the opening key point matches up, then you can lift it right off.

Step 3. Use a funnel:

Next, put a funnel in the gas receptacle. But if your lawn mower has an in built pouring nozzle, then a funnel is not necessary. The purpose of the funnel is to help you pour all the gas from the gas container into the tank without much spilling.

Step 4. Fill with gas:

Pour the gas from the can into the gas receptacle carefully and slowly. When using a funnel, make sure you don’t pour too fast as this can cause spillage. The neck of the funnel can allow only a certain amount of gasoline through at a time. So if you pour too fast, you might end up spilling some of the gas over the side of the funnel or on the floor. If your gas can has a built-in pouring nozzle, then you can pour as fast as you want, as this nozzle will regulate the rate at which the gas comes out.

Step 5. Don’t overfill:

Once the tank is filled up, you will be able to notice the gas level in the tank. Make sure that you don’t keep pouring after it gets full. Once you have enough gas in the tank, remove the funnel from the gas receptacle, then replace the gas cap and fasten it on tightly.

Fueling your lawn mower is actually pretty easy, as long as you have fresh fuel, avoid fuel with high ethanol, and use a stabilizer. Once you can stick to these basic rules, you’ll definitely get the best performance out of your machine.

Final remarks

Now that you know what gas to use for your lawnmower equipment, you also know that you don’t need to waste money on premium or expensive gas unless you have a high compression engine. We hope that this has been useful. Good luck!