http://www.fueltestkit.com/list_e10_engine_damage.htmlListed below are examples of problems and inconvenience that may occur from ethanol (alcohol) and contaminated E10 gas.
IMPORTANT: Most newer engines can run safely on E10 blends when gas is fresh and of high quality. Some engines are not designed for use of gasahol, and even following all precautions will cause damage. (Check your owner's manual for fuel recommendations).
However, E10 damage is most often due to gasoline "contamination", and would not have occurred had the E10 fuel met all ASTM quality standards.
E10 Contamination includes:
Gas at time of purchase contained over 10% legal limit for alcohol, excess water and/or tank not properly cleaned and dry prior to switch to E10.
Ethanol is a strong solvent and cleanser, and while small amounts will keep your engine clean, excess alcohol will wear down engine parts.
Ethanol's water-absorbing qualities are most problematic, but can be managed when fuel is stored properly and replaced often.
Ethanol Gasoline - General Problems/Issues:
1. Water Absorption!
Water Contamination (W/C) and Phase Separation (P/S) of gasoline;
Ethanol attracts, absorbs and holds moisture in fuel tank with increased occurrence of lean, water-diluted fuel.
2. Vapor lock or fuel starvation- Most common in carbureted engines, hot weather and/or at high altitude. (Ethanol increases gasoline's vapor pressure).
3. Drop in octane (after water absorption, P/S and W/C occurs).
4. Decreased fuel efficiency and mpg due to lower energy.
E10 Reformulated Gasoline = 111,836 BTU/gallon. Non-ethanol Gasoline = 114,000 BTU/Gallon. (Diesel and Kerosene Jet Fuel have about 129,000 BTU/gal).
5. Decreased life cycle of parts and engine.
6. Decreased shelf life of gasoline.
Engine/Parts Damage:
1. Wear and damage of internal engine parts.
2. Damage to metal, rubber, and plastic parts of fuel system.
3. Corrosion of metal parts in fuel system and engine.
4. Deterioration of elastomers and plastic parts.
5. Deterioration of non-metallic materials.
6. Fuel permeation through flexible fuel lines.
7. Drying, softening, stretching and/or cracking of rubber hoses,
seals and other rubber components.
8. Oxygen sensor damage.
9. Damage or premature disintegration of fuel pump.
10. Carburetor damage, including clogging.
11. Dirty and clogged fuel filters.
12. Clogging and plugging of fuel injectors.
13. Destruction of certain fiberglass fuel tanks.
14. Removal or fading of paint and varnish (both internal and external parts of engine).
15. Piston/bore failure through knock/pre-ignition.
16. Piston ring sticking.
17. Unsuitable ignition timing resulting in ignition failure.
18. Gumming-up of fuel injectors, carburetors, etc. due to release of accumulated deposits in engine from ethanol alcohol's solvent properties.
E10 Drivability Issues:
1. Engine performance problems, often simply due to lower energy of ethanol-blends.
2. Hard starting and operating difficulty.
3. Hesitation and lack of acceleration.
4. Stalling, especially at low speeds.