E15: This political decision could ruin your power equipment

On April 12, President Biden announced that he would allow the sale of E15 gasoline during the months of June-September, when it is normally banned. E15 is a moniker used to represent the percentage of ethanol (E15 = 15% ethanol) blended into the country’s gasoline. E10 fuel, or 10% ethanol blended gasoline, is sold year-round. E15 tends to be a few cents cheaper per gallon, so the announcement was widely viewed as an attempt to mitigate rising fuel costs. The difference between E10 and E15 may seem like a small, almost insignificant detail, but it can have enormous implications for your gasoline-powered outdoor power equipment. Read on to find out how.

A very brief primer on the science behind ethanol fuels

Ethanol is an alcohol-based fuel that is distilled from corn and sugar. It is biodegradable, non-toxic, and dissolves in water. It is used as an additive to gasoline to help oxygenate the fuel, causing it to burn more completely in internal-combustion engines. The higher the amount of oxygen molecules present in the process of combustion, the less harmful byproducts are created. Thus, ethanol gasoline produces cleaner exhaust emissions, theoretically leading to better overall air quality. There are pros & cons to ethanol fuels, some of which will be addressed in this article.

Why are we even talking about this?

Most modern automobiles utilize computer-controlled fuel systems, which sense the formulation of the fuel in the vehicle and adjust for it, creating optimal combustion conditions for the engine to burn the gasoline.

As a real-world example, a common vehicle repair is an O2 sensor replacement. This sensor is responsible for telling your car’s computer ‘brain’ the oxygen content in the fuel. Ethanol blend has an enormous impact on the oxygen present in gasoline. These sensors & computer systems allow late-model vehicles to safely burn E15 or E20, and some will even handle E85 ethanol fuel blends (although E85 requires special modifications to the engine). Thus, many of us can pull up to the fuel station, fill our cars with whatever ‘regular’ gasoline happens to be flowing through the pump that day, and be none the wiser. Our car’s computer figures it out from there, adjusting combustion characteristics as we drive away to safely burn the fuel, so no harm done. However, older cars and outdoor power equipment are only designed to handle ethanol fuel blends up to E10.

Since this article’s focus is power equipment, it’s worth a repeat: gasoline-powered outdoor power equipment can only safely run on fuel blends up to 10% ethanol (E10).

What happens if I run E15 in my lawn mower, chainsaw or other equipment?

Brace yourself, there is a little more science here. Blending ethanol—which again is a form of alcohol—into gasoline alters the fuel characteristics for outdoor power equipment in important ways. First up, alcohol is more corrosive than gasoline. Thus, it can—over time—damage rubber parts, fuel lines and gaskets inside of fuel systems.

Next, alcohol burns at a higher temperature than gasoline, so the more ethanol in your fuel, the higher the combustion temperature for the engine. Most outdoor power equipment engines are air-cooled (as opposed to liquid-cooled, like vehicles) and not designed to handle these higher temperatures. This can lead to overheating and major/catastrophic engine failure.

Also, ethanol is a polar solvent (again, alcohol, remember?), and thus has an affinity for water. It will literally pull water vapor out of the air in standing fuel tanks and/or cans. Being that outdoor power equipment does not get used nearly as often as a vehicle typically does, and the fuel storage systems are much smaller, power equipment is susceptible to picking up significant quantities of water in the gasoline. This increases the likelihood of water-in-gas failures that cause your equipment run badly, and require it to go into the shop for expensive fuel-system repair work.

Finally, ethanol is more volatile than gasoline, meaning it is more prone to evaporation. Thus, as ambient temperatures get higher—like they do in June through September, the height of summer—excessive evaporation of the volatile chemicals in ethanol can lead to vapor-lock issues causing your equipment run badly. (On a side note, it also makes ethanol blended fuels a poor choice for storage of outdoor power equipment over the ‘off-season.’ As the ethanol evaporates, the overall octane of the gasoline falls, and becomes so low that the equipment will struggle to start the following season. The fuel octane is lowered to the point that the gasoline becomes ‘dead’ and the machine’s ignition system will not be able to create adequate combustion parameters to start. But I digress…)

It is also very important to note that almost without exception, any damage caused to an outdoor power tool’s engine by fuels blended in excess of E10 are NOT covered under manufacturers’ warranties. If this occurs, you will likely be left needing to replace an expensive piece of power equipment out of your own pocket.

How will I know what blend of fuel I’m getting at the station?

Not all fuel stations sell E15. Stations that do are required to post signage stating that their gasoline is E15, as opposed to the standard E10 sold all over the country. Thus, the only thing really required of us if we’re purchasing fuel for our outdoor power equipment is to pay attention to any signage relating to E15 before we begin fueling.

Can I avoid ethanol fuels altogether?

Yes! It takes some diligence, though. Non-ethanol fuel or ‘clear’ gasoline is available at places all over the country. Here in Oregon, non-ethanol fuel can be sourced typically in either 87- or 92-octane. Non-ethanol 92-octane fuel is an excellent choice for outdoor power equipment. It helps you avoid all the pitfalls of ethanol fuel in outdoor power equipment, as detailed above. Additionally, ‘clear-92’ fuel has an additive package superior to lower-octane fuels, allowing it to hold it’s octane for a longer period of time. This is ideal for the typically seasonal usage & storage requirements of outdoor power equipment.

Here at CRE, our best-practice recommendation is to source and use ethanol-free 92-octane gasoline in all of your outdoor power equipment. For mixed-fuel handheld equipment, we offer a pre-packaged high-octane ethanol-free mixed fuel product for sale in the store. For larger quantities of ethanol-free fuel, a simple Google search of your surrounding area for ‘non ethanol gas near me’ should get you on your way!

With a little bit of research and diligence, you can save a little money at the fuel pump AND set yourself up for success with your outdoor power equipment.

Want more information? Our Service department HERE is available to help, or stop by the next time you’re in downtown Canby!