However many older car engines have plastic and rubber components which can become brittle over the engine life. These components are susceptible to alcohol and can disintegrate when exposed to alcohol, causing leaks and blocking filters and fuel systems.
Also, years of accumulated dirt and sediment will have built up inside engine components, should this be washed off by the ethanol it will contaminate the engine oil and block filters eventually leading to engine seizure.http://www.brighthub.com/environment/renewable-energy/articles/76658.aspx
Ethanol is said to attack some rubber components such as fuel lines and seals and gaskets.
__________________________________________ Answer 2
There are huge variations in what cars can be modified to use ethanol due to the car manufacturer and year the car was made. If car was made after 1985, ethanol should not be as corrosive as for cars made before 1985.
Higher concentration (for example E85 or fuel with 85% ethanol) will have corrosive effect on rubber, plastic and/or aluminum parts that are not designed for it. Aluminium can be protected by anodizing it which will add protective layer to it.
Smaller concentration (E5 or E10) will not affect unprotected aluminum parts at all. They might still have negative impact on unprotected rubber parts (fuel lines, injector seals etc). Fuel tanks (or the lining within) might have problems withstanding the ethanol and should be replaced with suitable tank. http://wiki.answers.com/Q/Does_ethanol_have_a_negative_effect_on_rubber_fuel_lines_andor_carburetors
My apologies. I thought you were referring to newer non-automotive engines.
I have a couple of old chainsaw that are useless.
Some of the stuff “designed for it” and meeting epa and LEAP guidelines is failing within two years... I have samples.