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Ethanol in Two-Stroke Engines

written by: Tarun Goel•edited by: Lamar Stonecypher•updated: 8/7/2011

An exclusively ethanol two stroke engine is presently not possible. However ethanol blended gasoline can be used to run your vehicles. Find more about how and when to use ethanol blended with gasoline. Also know about what your company has to say about the compatibility of your vehicle with ethanol.

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    Two stroke engines are used not only in automobiles (rarely in the US), but also in lawn mowers, chainsaws, minibikes, and two wheelers. Invented in late 1880s by Dugald Clerk, the design became immensely popular in the 19th and 20th centuries. Gasoline was used mainly as a fuel and, as the cost of petroleum products started to rise, people started using blended or adulterated fuels to power their two stroke engines. However, ethanol based gasoline was not suitable for all the engines. Even today when the automobile technology has scaled great heights, gasoline blended with ethanol is not deemed fit for all types of two stroke engines.

    Moreover, many environmentalists believe that ethanol is not a "net positive" energy source as a fuel. The processing and manufacturing of ethanol and the ill effects of producing its constituent ingredients have a negative impact on the ecological balance. Using ethanol as an alternative fuel itself has been questioned by some experts.

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    Ethanol as Fuel

    Ethanol is used as an additive fuel with gasoline. Brazil and the US are the two countries that are the greatest consumers of ethanol blended gasoline. Despite the fact that ethanol is solving the energy woes of nations (somewhat), it is also affecting the performance and efficiency of two stroke engines at the same time. Running an exclusively ethanol-based two stroke engine is not yet possible, and the most popular ethanol blend is E10, containing 10% ethanol by volume.

    Disadvantages of using ethanol in two stroke engines

    The following list will briefly describe the major disadvantages associated with ethanol as fuel for your two stroke engine vehicle or machine.

    1. Not all carburetors will support ethanol-based gasoline. Some carburetors will not mix air and fuel properly if ethanol is blended with gasoline, resulting in lagging performance of your vehicle or machine. Using ethanol with two stroke engines will require recalibration of the vacuum system and that is an expensive process. Moreover it will also require you to change accelerator pumps and foam floats, which are however mostly applicable to old engines.
    2. Phase separation of ethanol is another major problem that often occurs when the fuel comes in contact with water. When water vapor due to condensation accumulates in the fuel tank, the ethanol reacts with the water and settles down into the bottom of the fuel. The blended mixture is no longer uniform, resulting in irregular engine performance. It can even result in sudden engine breakdown.
    3. Soft plastic and rubber components of your machines might react with ethanol-blended gasoline, resulting in engine malfunctioning. Modern fuel tanks and machine components made of fiberglass can be affected as well. Leeching of resin is one common problem that occurs when ethanol reacts with plastic or fiberglass components. Most commonly filters and injectors become victim to this reactive environment.
    4. Ethanol based gasoline contains a higher percentage of oxygen as compared to conventional gasoline. Not all the two stroke engines can work efficiently with increased oxygen content because they are not designed for such fuel mixtures. Most commonly, small machines like chainsaws and lawn mowers face problems if they are operated on ethanol based fuels.
    5. Ethanol based fuel, if spills on your vehicle or machine parts, will result in blistering. Paint does not resist ethanol.
    6. If the percentage of ethanol in the vehicle is too high, it might very well result in engine seizure, making a huge dent in your pocket. Engine seizure not only costs a lot to repair, but it also reduces the resale value of your vehicle.
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    Importance of Reading Instruction Manual

    The instruction manual is something that almost all of us choose to ignore, but the user's guide or owner's manual explains all the dos and Manual don’ts related to your two stroke engine. If your machine is compatible or not with ethanol based gasoline, the instruction manual will state this very clearly. It becomes even more important to follow the instruction manual when your vehicle is covered under warranty.

    If it is too tiring to read the complete instruction manua,l then the best thing to do is to read the particular section mentioning the conditions under which warranty will not be provided. Manufacturers speak big while selling you a product, but when it comes to replacing or repairing products under warranty, they are not so polite. However, if you read instructions mentioned in your user manual, it clearly mentions the things, components, and activities that can affect your warranty claim. Using ethanol is strictly restricted by some manufacturers and you should know about it if you want your two stroke engine to perform well and have a long life.