1998 Johnson Evinrude "EC" 150, 175 FFI Service Manual, P/N 520211, Page 25Get this manual
Fuel Requirements
Minimum Octane Models 150,175 Recommendation See fuel classifications below(R+M)2 AKI"
Preferred Fuel: Any regular unleaded, regular leaded, or premium unleaded gasoline having the recommended octane ratingAcceptable Fuel: Any of the above gasolines with up to the following percentage alcohol by volume: 10 ETHANOL or METHANOL with cosolvents Unacceptable Fuel: Do not use any gasoline having more than 10 ETHANOL or more than METHANOL even if it contains cosolvents or corrosion inhibitor, regardless of octane ratingOMC products have been designed to operate using the Preferred Fuel or Acceptable Fuel; however, be aware of the following: The boat's fuel system may be different regarding use of alcohol fuelsRefer to boat owner's manual Alcohol attracts and holds moisture which may cause corrosion of metallic parts of the fuel system Alcohol extended fuels can cause engine performance problems All parts of the fuel system should be inspected frequently and replaced if signs of deterioration or fuel leakage are foundInspect at least annually