Written by Hoon Ge, MEG Corp
A video on the West Central Tribune’s website on July 8 titled “Why small engines go bad” contained several errors and misconceptions about the use of ethanol-blended fuel in equipment like lawn mowers and chain saws powered by small engines.
As many readers probably know, all regular unleaded fuel sold in the United States contains 10 percent ethanol. Blending ethanol in our fuel supply helps improve air quality and reduces America’s dependence on foreign oil. Contrary to what was said in the July 8 video, ethanol blends up to 10 percent (E10) are also safe to use in small engines.
The person interviewed stated that E10 only last two weeks, which is false. The minimum shelf life on E10 is six months. It may even last longer than one year under proper storage conditions.
Another myth perpetuated in the video claimed that ethanol in fuel absorbed humidity and led to excess water in your lawn mower’s fuel tank. Truth is, water in fuel occurs when it condenses out of the air when the air temperature drops. Straight gasoline can absorb up to 300 parts-per-million (ppm) of water before free water will form, which can cause engine damage. E10 can absorb up to 5000 ppm before free water will form.
As long as you use a fuel tank cap that seals tightly, and drain the fuel from the tank before storing your piece of equipment for an extended period, you do not need to worry about ethanol resulting in excess water in your tank and causing damage. Another option for safe storage in the offseason is keeping the tank full and sealing off the vent.
To correct other misinformation in the video, ethanol blends completely with gasoline and will not separate. It is physically impossible for a concentration of ethanol to reach the engine as claimed in the video.
The only time ethanol and gasoline can separate is in the presence of a high amount of water. This is an usual circumstance and occurs when water percentages exceeds 0.5 percent, which is a very high percentage. E10 when blended with motor oil will not separate, once E10 is bonded with gas it will blend with motor oil.
Another myth in the July 8 video claimed that ethanol causes damage to a small engine’s carburetor. Since ethanol burns cleaner than gasoline, nothing could be further from the truth. If you’re having trouble with your carburetor, it’s likely being caused by old gasoline or gasoline that wasn’t stored properly.
There are two options when you’re done using your piece of equipment for the season: drain the fuel tank before storage or keep the tank full and seal off the vent. There is no need to spend extra money on ethanol-free “premium” fuel that doesn’t contain ethanol.
As summer winds down and the time draws closer to putting away our lawn mowers, chain saws and weed whackers for the winter, be sure to drain the fuel tank, or keep the tank full and seal off the vent. By taking these steps and following the instructions in the owner’s manual for proper storage and fueling, you can rest assured that E10 will power your small engine for a long, long time.
Written by Hoon Ge, founder of MEG Corp, a leading fuel consulting company based in Minneapolis. Ge is a chemical engineer with over 25 years of experience in the petroleum industry, including refining, additive formulation and alternative fuels.