Important E10 Ethanol Fuel Precaution: Ethanol alcohol fuel blends expire in 90 days; When exposed to excessive water, they may expire even sooner.
Studies have shown that after only 100 days, alcohol fuels absorb enough moisture to phase separate. Octane will drop when fuel phases separates...
If you are not monitoring or "testing" your gas for alcohol and water content, we recommend replacement of gas in your fuel tank at least every 2-4 weeks to avoid alcohol and water related engine problems.
Alcohol blend fuels become contaminated by water dilution (phase separation) very quickly. When this occurs, gasoline octane of the fuel in the tank may frop as much as 3 points...
Protect your engines from purchase of lean or diluted fuel (low octane)...
Simple, easy, accurate. Mix small amounts water and fuel from pump or tank into the test tube included, shake to mix the contents. Wait a few minutes until settled. An increase in the amount of water on the gauge indicates that alcohol is present in the fuel. The gauge will also indicate the percentage of alcohol. View testing procedure and instructions.
Fuel that tests greater than 10 % alcohol is "bad" and should not be used in conventional engines. Some motors (airplanes and certain marine engines) can NOT use fuel that contains alcohol. Check with the motor manufacturer for fuel recommendations.
By 2008, most gasoline stations have switched to ethanol-blended fuels, replacing MTBE, for oxygenating fuel. The gas pumps are not required to disclose that gasoline contains ethanol alcohol in almost all states!
When fuel absorbs moisture the octane reading can dramatically decrease.
Fuel that has experienced water contamination (W/C) and phase separation (P/S) will decrease about 3 octane points...
Many refer to this as "lean fuel" or "diluted fuel".
If you purchased fuel with an 87 octane level, after W/C and P/S will decrease to only 84, (an unsafe level for most engines).
Proper management when using alcohol-blend fuels will avoid this problem.
Some people chose to purchase a higher level octane blend when purchasing E10 fuel - to prevent octane from reaching a dangerously low level if fuel contaminates.
To avoid wasting money on gas that will contaminate quickly always purchase high quality fuel, test for water and alcohol before purchase, follow necessary precautions, and refill tank often.
Replacing fuel in your tank every 1-2 weeks will usually limit the occurence of PS and WC.
Of course, there are other situations when irregardless of how fresh fuel is, the fuel will go bad - causing decrease in octane and other negative effects on ingredients contained in fuel.
Running on gas with the appropriate octane rating will offer best performance and increase the useful life of the engine.
Many engine owners that have experienced unnecessary and avoidable damage with E10 is often due to sub-normal octane gasoline.
View list of common problems and engine damage from E10 gasoline.
To maintain the octane rating listed at time of purchase, following simple ethanol precautions to protect fuel quality.
Precautions (http://www.fueltestkit.com/ethanol_engine_precautions.html) should be all you need to do to assure engine is running on stable, high quality fuel with an appropriate octane level, recommended by your engine manufacturer.