The fuel distributors or gas delivery truck drivers mix ethanol alcohol into the gasoline. 10% or lower alcohol content of fuel is safe for most engines.
Unfortunately, carelessness while mixing the ethanol into fuel, can result in too much alcohol being added to the gas blend. Fuel that tests greater than 10 % alcohol is unsafe and should not be used. Some motors (airplanes and certain marine engines) can NOT use any fuels that contain alcohol.
Adding external fuel system products, which contain alcohol to your fuel tank will increase the alcohol content over gas over legal limit of 10% - Check MSDS and chemical ingredients before adding any fuel additives and gas treatments. Fuel system cleansers, water removers and oxygenators often are alcohol based.
What laws and monitoring protects consumers from purchasing gas with illegal ethanol content (above 10%)?
State and Federal Laws allow up to a maximum of 10 % alcohol in E10 gasoline.
There is very limited monitoring of alcohol levels at fuel at pumps. Gas station owners are not legally required to check fuel delivered has correct amount of ethanol - Gas stations usually check water content of tanks daily, but are only beginning to realize that the fuel they received does not meet state and federal guidelines.
Excess water in tank and pumps is a sure indicator that E10 fuel contains too much ethanol, when external sources of moisture and water contamination are eliminated.
As consumers perform more testing of fuel at pumps (with portable fuel test kits), gas station owners have become more aware of the varying content of ethanol in fuel supply they purchase.
Most people don't realize when fuel is above legal limit of alcohol until it's too late. Performance problems, followed by damage to engine will result from high alcohol fuel in a conventional vehicle (Non-Flex Fuel Vehicle). Some pumps have tested as high as 40% alcohol content for E10.
In several states the gas pumps are not required to disclose (label pump), when ethanol is added to fuel.
Simply put, ethanol (alcohols) are an excellent SOLVENT (dissolves plastic, rubber, fiberglass and more), and unlike MTBE ethanol is hygroscopic and will ABSORB WATER, which can cause serious problems to some engine motors. The higher the alcohol, the greater the damage.
High Alcohol Content in Fuel WILL Damage Your Engine.
PREVENTION is your best defense...
Gas containing ethanol (alcohol) content over 10 % will have negative effects on your engine's parts and performance.
E85 can only be used in engines designed to run on this high alcohol fuels (FFV's -Flex Fuel Vehicles, aka "Green" cars").
ACE (American Coalition for Ethanol) and other ethanol promoting organizations have submitted proposal to increase E10 to E15 by December 2009. Engine manufacturers currenty only approve use of E10, 10%.
Understanding Effect of High Alcohol Content on Engines
Interpreting and Understanding Test Results
Note: The following information is guidelines only, engine affects from alcohol fuels will vary. Consult a certified mechanic for more information. Always follow equipment's fuel recommendations and review your owner's manual and warranty statements for fuel recommendations.
Alcohol Content Results
Effects of percent (%) alcohol on engines.
Up to 10% alcohol = Legal limit for E10 -Safe for most engines.
11 to 15% - * Risky - Use with extreme caution. Engine performance problems will usually occur, eg. stalling. Fuel should be drained (discarded), and replaced with fresh gasoline. Although possibly unsafe, if only a small amount of fuel is left in tank tests over 10% alcohol, (eg. less than a 1/4 tank full), filling the tank with a high octane (93) fresh gasoline can be considered. After filling tank, check fuel again to check alcohol percentage has decreased to a safe level.
See important notes below.
16-25% = Very Risky - Do Not Use - Will experience varied engine performance problems, including unable to start, frequent stalling, difficulty accelerating, and more. Will reduce life of engine. It is recommended that fuel be immediately drained and discarded. Do not run your engine on this unsafe level of alcohol. Damage to your engine and parts will occur, sometimes immediately. How soon this occurs is dependent on several factors, including age of engine, type of engine, parts used, and condition of engine. See important notes below.
26-40 % Severe risk and danger - Do Not Use -Affects will be same as listed above for 16 to 25 %, but damage will appear much sooner, sometimes immediately after running one time on this dangerously high alcohol content level. Performance problems will be greater, and older or poorly tuned engines most likely will be unable to start on this very high level of alcohol. Black smoke from engine will be apparent. Fuel discoloration and a strong odor is proof that gas is contaminated. The dirtier your engine, the greater amount of gunk released will be noticed. Engines that have older, dirty parts will notice clogged fuel filters very quickly. See important notes below.
Over 40% - Engine most likely will not start. Do not use - Severe damage will occur. Damage to engine will be permanent, engine may not be repairable. See important notes below.
- Resist draining tank and using old contaminated and high alcohol fuel in another engine (eg. lawnmower).
- Certain fiberglass tanks, older outboards, and a small number of marine engines prohibit use of alcohol fuels.
- Check with the engine manufacturer or check your owner's manual for fuel recommendations.
- Over the past 5-10 years, most engine manufactures have changed or replaced parts that are not resistant to alcohol, in anticipation
that ethanol blend fuel use would increase and become the #1 fuel sold to the public (They were right!).
- In a short period of time, high alcohol levels, running through engine. will "clean" the engine parts and "dissolve" rust, resin, plastiic and rubber parts, fiberglass (without protective layer) and other old caked-on matter.
- Alcohol's solvent and cleaning affect, results in clogged and dirty filters and deposits in the carburetor.
Some dissolved matter will leave "gummy" deposits and black sludge.
- Contaminated gasoline, is especially noticeable in "fuel-injected" engines, because the gas returns to the tank.
Matter/deposits/rust/resins etc; that the alcohol has "cleaned-off" and removed, will be noticed in the gas tank.
Fuel filters and the carburetor will appear dirty.
- Gasoline that contains excessive alcohol and/or has become contaminated will usually have a noticeably strong odor and change in appearance. Fuels that have phase-separated, will show 2 or 3 distinct layers of gasoline and water/ethanol layers.
- MARINE: Since 2006, most major outboard boat manufacturers approve use of E10 fuels in all newer engines.
Mercury, who once prohibited alcohol in all their engines, now says E10 (10%) is ok.
Newer marine engines, that are properly tuned are most resistant to too high alcohol content in gas.
- AUTO: All major automobile manufacturers, approve use of E10 fuels for new cars. For antique cars, or models made prior to 1998, check with the automaker. E85 gas cannot be used in a conventional auto.