It is generally accepted in the engine industry that Ethanol is bad, but what does bad really mean? Most enthusiasts have heard of the storage issues related to Ethanol blended fuels, but what is the best course of action concerning these issues? Do Ethanol additives help the problem? Recently, even the mainstream media has picked up on this growing problem such as this article that was recently posted on FoxNews.com. Let’s address each of the issues one by one, and present some viable options for dealing with these issues.
Ethanol is hygroscopic. No, that is not some foot fungus. It means that Ethanol likes water. That is a great quality when you order on scotch on the rocks. However, water makes for a pretty lousy fuel.
During periods of extended storage, Ethanol tends to draw in atmospheric moisture which can lead to a build-up of water in your fuel cell or container. Because the density of water is greater than gasoline, the Ethanol/Water mixture separates from the gasoline and settles to the bottom of the fuel cell. Industry refers to this as Phase Separation, and because the pick-up is located on the bottom of the fuel cell, the first thing sucked up when you try to crank the engine is the Ethanol/Water mixture.
Not only will this cause your lawn mower not to start in the Spring, it will also pump a corrosive cocktail through your engine, and since some of that water/Ethanol cocktail ends up in your crankcase, your motor oil is not very happy either.
Speaking of corrosion, many people do not realize that Ethanol is not transported in the pipelines with gasoline. The ethanol is added later just prior to delivery to your local gas station. You see, ethanol is very corrosive, so the pipeline companies don’t want the Ethanol eating the pipelines.
Which leads us to our next issue, fuel system corrosion. While modern fuel injection engines feature materials compatible with Ethanol, Carburetors are made from alloys of Zinc and Aluminum, both of which are susceptible to corrosive properties of Ethanol. Many carburetor rebuilders have reported seeing “white” deposits inside the Carburetors, and detailed laboratory analysis confirmed that these deposits are result of corrosion from Ethanol blended fuels. The greater the ethanol concentration the worse the problem, and periods of extended storage only worsen the problem. In fact the US Department of Energy’s Oak Ridge National Laboratory warns against the use of Zinc or Aluminum with Ethanol. Additives designed to help prevent Phase Separation generally contain Alcohol which can make the corrosion problem worse.
If the Ethanol was not bad enough, the water that comes along for the ride just adds to the corrosion problem. The moisture that passes through the fuel system and ends up in the crankcase can lead to rust inside the engine, and water depletes to additives in your motor oil that are designed to prevent rust and wear – a very negative 2 for 1 deal. The negatives effects from Ethanol on your fuel system don’t end at corrosion. Because Ethanol is an alcohol, ethanol dries out the rubber components in your fuel system. This leads to cracking and brittle fuel lines, floats, seals and diaphragms. Obviously, leaky fuel lines are a safety hazard. These material compatibility issues are even worse for small engines. The Carburetors on a typical small engine, like your 2 stroke leaf blower, use a diaphragm style fuel pump. The ethanol in the fuel causes the diaphragm to harden. The fuel pump stops working, and now your leaf blower won’t run. So what do you do if using an ethanol free fuel is not viable option? First, when switching to a high Ethanol content fuel, the fuel lines, fuel cell and other rubberized components must be replaced with materials that are compatible with high ethanol content fuels. All modern (since 2007) cars feature these upgraded materials that are compatible with Ethanol blended fuels (that is one of the special parts in a flex fuel vehicle).
The other step to take regards storage. The best way to prevent phase separation is NOT adding another bottle of fuel stabilizer into your tank. A fuel additive with a corrosion inhibitor for your carburetor is all you need. The best way to prevent phase separation is by making sure the fuel cell is full when you put your vehicle, lawn mower or boat away in storage. With less “room to breathe” the fuel cell will not absorb enough moisture to cause phase separation. If the fuel cell can’t be stored full, the run it dry before putting it away for Winter storage. The fastest route to phase separation is a partially full tank of ethanol blended fuel allowed to breathe in atmospheric moisture.
Even if you follow all of these guidelines, Ethanol has one last curveball to throw at you – Vapor Pressure. Ethanol affects the nature of how gasoline evaporates, and that changes how the fuel system must be tuned. Because the ethanol content in pump fuels varies, the effect on vapor pressure varies, which means the performance qualities of the fuel varies from tank to tank.
Obviously, the best course of action is to use an Ethanol free fuel. However, these fuels are hard to find in metropolitan areas due to clean air regulations, and these fuels cost more. Fortunately, the worst side effects of ethanol can be dealt with by using the correct materials in the fuel system, taking care to use a corrosion inhibitor additive if you have a carburetor, and making sure the tank is full when you put away your vehicle, lawn mower or boat for the Winter.