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Can You Use Ethanol-Free Gas in a Weed Eater? Know The Facts

Can You Use Ethanol-Free Gas in a Weed Eater? Know The Facts

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Paul Brown

If you’re ready to prepare the premix for your 2-stroke weed eater and just realized that the gasoline you have is ethanol-free, you might be wondering whether you can use it in your machine or not.

So, can you use ethanol-free gas in a weed eater? Yes, you can use ethanol-free gas in a weed eater. In fact, ethanol-free gas is the best choice for two-stroke weed eaters. Ethanol-free fuel has a longer shelf life and reduces risk to small engines caused by moisture in the tank.

But before you load up your weed eater with ethanol-free gas, it’s important that you learn all about the pros and cons of using this particular fuel source. We’ll also discuss some tips to help you create the best pre-blended fuel and explain why, in most cases, just purchasing an ethanol-free commercial premix is your best bet.

What Is Ethanol-Free Gas?

Ethanol is a type of alcohol that we can also find in beverages and drinks. This compound is oxygen-rich and has the power to oxygenate the fuel (source). While regulations throughout the world vary, the gas that you can buy from any gas station typically contains at least some ethanol.

As the fuel becomes oxygenated, it tends to burn thoroughly, which, in turn, produces fewer emissions and has a lower environmental impact (source). On the other hand, ethanol tends to attract water, which the engine of your 2-stroke cannot process correctly.

As the ethanol and water produce bubbles in the fuel, you will notice decreased performances and, eventually, engine failure.

For more information, read my in-depth review on Ethanol And The Growing Issue Of Small Engine Problems

Pros and Cons of Ethanol-Free Gas

Ethanol can be damaging for your simple 2-stroke engine. Yet, we can find ethanol in every batch of gasoline on the market. If you are still unsure about which is best for your outdoor equipment, check out this list of pros and cons.

Pros of Ethanol-Free Gas

  • Improves performance
  • It avoids corrosion of the engine, gums, and tank.
  • Prevents the engine from flooding as well as water damage
  • Allows you to use the premix and gasoline for longer
  • Your 2-stroke engine won’t need to adjust the amount of fuel injected in the engine
  • There are several other environmental concerns related to the production of ethanol (source).

Cons of Ethanol-Free Gas

  • Ethanol allows the gasoline to burn through and avoid fuel wastage
  • Such a combustion process eliminates the danger of increased CO2 emissions.
  • It is more readily available from distributors and dealers

Why Is Ethanol Bad For Your 2-Stroke?

Ethanol-free gas is recommended by manufacturers of weed eaters and other gas-powered yard tools.

Ethanol attracts water in the engine. While four-stroke engines tend to be more resilient to it, 2-stroke can suffer significant damage from the ethanol content in gasoline purchased at the pump.

  • Ethanol causes changes in the combustion process
    • Thanks to their software, cars adjust how much fuel enters the engine based on the ethanol content, your simple weed-eater will be less likely to cope with the changes.
    • Typically, any ethanol content that is higher than 10% will cause a reduction in the level of energy emitted and differences in the spark time and fuel-air ratio.
  • Water absorption in the tank
    • Over time, ethanol will attract moisture and water to the fuel tank. Whether moisture comes from internal condensation or external sources, it can contribute to the engine corrosion and malfunctioning.
  • As a solvent, ethanol can release deposits in the fuel line and corrode plastic
    • Residues created by the oil and gas that often end up sitting at the bottom of your fuel tank are damaging for the engine. While the fuel filter’s main task is to filtrate such residues, ethanol has the power of breaking them down into smaller particles that can now pass through it.
    • At the same time, ethanol can corrode and dissolve plastic. In older equipment, this can cause severe problems to the tank and gaskets.

Source – North Caroline College of Agriculture and Life Sciences

Here’s what various manufacturers recommend related to ethanol-content and octane ratings for their outdoor power tools including weed eaters:

ManufacturerMaximum EthanolMinimum Octane Rating
Briggs & Stratton10%87

I could go on but I think the picture is clear enough. 10% ethanol is the max you want to be putting in your gas-powered yard tool. And many manufacturers encourage the use of ethanol-free fuel to prevent damage.

In fact, Husqvarna specifically states on their website that “while E10 fuels are approved for small engine equipment usage, it is not recommended, especially in handheld products” (source).

Watch this video from Husqvarna on the problems of using too high of ethanol content in small engines:

Ethanol and Your Outdoor Power Equipment. How to Prevent Issues.

Should I Buy Premix Fuel Or Mix My Own?

Since there is no oil injector in the engine of your two-stroke, you have to use gas and oil mixed yourself or buy a pre-blended fuel. I always recommend buying commercially prepared premix like Trufuel (link to Amazon) because it contains ethanol-free gas and uses high-quality synthetic oil.

If you choose to mix your own, manufacturers recommend limiting the percentage of ethanol to 10%. Modern 2-stroke engines can manage that amount without significant damage.

If you are planning to mix your own gas and oil, you should follow these tips:

  • If your weed eater is not in use for over a month, empty the gas tank and line to avoid the engine’s potential water damage. With the tank empty, start it and let it burn out the remaining fuel in the carburetor.
  • When creating a homemade gas and oil mix, store it for no more than 60 days. (See Does Premix Fuel Go Bad? HomeMade Vs Commercial Gas-Oil Mix)
  • If you need to extend the shelf life of the gas before mixing, add stabilizers.
  • Do not leave the mixture uncovered or in a plastic container.

For a comparison of commercial premixed fuels for 2-stroke yard tools, read my side-by-side review of 4 of the top premixed fuels on the market.

How To Avoid Ethanol Damage In 2-Cycle Engines

Commercially prepared premix is best but if you are going to mix your own, follow these best practices to minimize risk to your weed eater’s engine:

  • Use gasoline with a maximum of 10% ethanol (ethanol-free is better)
    • Remember that low percentages of ethanol are not as damaging for the engine. In any case, remember to avoid leaving leftover fuel in the tank or fuel line for prolonged periods.
  • Use high octane fuel
    • Octane is a rating system that expresses the quality of gasoline. Octanes refer to the strength gasoline can withstand before igniting.
    • The higher such value is, the less gas gets misused in the combustion process, increasing performance and mileage (source). Always try to feed your weed eater gasoline that has a higher octane level than 89.
  • Use stabilizers
    • Stabilizers have the function of bonding to the moisture particles, which are absorbed back by the fuel. Such a process prevents the formation of bubbles in the fuel.
    • You will need to add stabilizers in every batch of homemade premix you are blending for your weed eater. If you opt for ethanol-free gas, stabilizers are not as essential. See Adding Fuel Stabilizer To Ethanol-Free Gas: Is It Needed?

Again, it’s best these days is to just avoid mixing your own gas and oil and go with a commercially prepared premix. These products are not only ethanol-free, but they also include high-octane fuel and ashless synthetic oil.

Even better, premixed fuel boasts precisely measured parts that aim at preserving the wellbeing of the engine. They even include stabilizers to prolong shelf life.

The best premix fuels on the market for weed eaters are:

Stihl Motomix93Check Price (Link To Amazon)
Trufuel92Check Price (Link To Amazon)
Husqvarna XP95Check Price (Link To Amazon)

All of these use ethanol-free gas and premium synthetic oil at a precise 50:1 ratio.


Ethanol-free gas is your best option for maintaining your weed eater’s 2-stroke engine.

As a type of alcohol, ethanol can attract water and moisture towards your fuel tank and line.

Remember, gasoline that contains more than 10% ethanol can have seriously damaging effects to the engine of your weed eater by breaking down residues in the tank that is now to flow into the engine. It can lead to an obstruction of the filter and crankcase and eventually engine failure.