1990 Johnson Evinrude "ES" 40 thru 55, P/N 507872, Page 26Get this manual
Fuel Requirements
Minimum Octane Models Recommendations (R+M)2 "AKI" "RON"
45, 55 40, 48,50
See fuel classifications below See fuel classifications below
Preferred Fuel: Any regular unleaded, regular leaded, or premium un leaded gasoline having the recommended octane rating and not extended with alcohol is the preferred fuelAcceptable Fuel: Any of the above gasolines with up to 10 alcohol by volume:
10 ETHANOL METHANOL with cosolvents Unacceptable Fuel: Do not use any regular unleaded, regular leaded or premium unleaded gasoline having more than 10 ETHANOL or more that 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 Fuelhowever, be aware of the following: The boat 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 All parts of the fuel system should be inspected frequently and replaced if signs of deterioration or fuel leakage are foundInspect at least annually Alcohol extended fuels can cause engine performance problems&