On all my motorcycles/atv's I had to start draining the carbs when putting them away for a week or longer due to the fact that they wouldn't start after sitting with E10 in the carbs. Before I was just letting them run out by turning the gas tanks off. It still left fuel in the bowls and I was pulling the carbs every time and cleaning all the gunk out of them. I think it's because the orifices on the jets are so small. So rebuilding 5 carbs to go riding for a day got old fast. I could go to race gas but have had no issues since I started draining the bowls.
I have never had any issues with my lawn mower, I leave gas in it all winter and it still works.
engines have a few things different then a regular gas engine. Internal engine parts receive a nitride coating to resist the formic acid created in the combustion of e85 due to the fact that it absorbs so much moisture. They also have different spark plugs and injectors that pulse more fuel.
SEMA released news of a study that shows e15 and e20 can damage engines. The Coordinating Research Council (CRC) tested 8 vehicle types from '01-'09 model years with various popular engines. Two engines failed while running e15 and e20 gas. And from the report "ethanol increases water formation, which can then create formic acid and corrode metals, plastics, and rubber, which is against the EPA's approval of e15 in '01 and newer vehicles" says SEMA, who has asked congress to enact legislation to stop the sale of e15 until further tests can be done.
Thanks for the report Wolf, good read!
My mower started having issues 2 summers ago. Now every year when i start it up i have to spray carb cleaner into the air intake, then she starts up, though out the year once or twice i have to repeat with carb cleaner to keep her starting smooth.
Last year i got out a mower that had been sitting for about 2-3 years without being run, it was my sisters mower and she moved away and left it sit with the old gas in it. I bought it off of her and tried to get it running. I could get it to start but it seemed like it was always starving for gas and would stall randomly. I pulled the carb out of it and tore it apart and it was totally covered inside with varnish and the needles and float were all clogged up. I know for a fact that she used regular low octane gas from the gas station. leaving this gas in the mower without any type of additive will mess up the carb. I'm sure its not good for injectors after seeing the carb.