Re: Is it okay to run the E10 gas in the Merc 170HP
E10 or 10% ethanol is the norm around here, can't get any gasoline other than that, and that's state law actually.
The biggest thing you should know is ethanol likes water. So exposing E10 fuel to the atmosphere will have more tendancy to absorb moisture and cause problems than non ethanoled fuel. Running a water separating fuel filter is a good idea, not like you wouldn't want to if the gas didn't have ethanol, and make sure you're fuel tank cap and vent are in good condition. I've had problems with water in my carb over the winter so now I remove the carb, drain it, and store it inside as preventative maintenance.
Other than that, E10 gas is no different. The 10% amount was determined the limit for ethanol for compatibility with existing fuel system materials- rubber seals, plastics, etc. If you run higher concentration, like E85 (85% ethanol) then you need a compatible fuel system otherwise the ethanol will dry and rot out many types of seals, and plastics I believe. For E10, you don't need to do anything.
