1989 Johnson Evinrude "CE" 9.9 thru 30 Service Manual, P/N 507754, Page 29Get this manual
Fuel Requirements
Minimum Octane Models Recommendations Pump Posted "RON"
See fuel classifications below
Preferred Fuel: Any regular unleaded, regular leaded, or premium unleaded 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 than METHANOL even if it contains cosolvents or corrosion inhibitor and regardless of octane ratingAlcohol extended fuels may result in engine running quality problems, vapor lock or "fuel starvation" problems, or moisture absorption (phase separation) problemsIf running quality problems are experienced, switch to gasoline without alcohol as described in Preferred Fu el OMC products have been designed to operate using the Preferred Fuelor Acceptable Fuel; however, be aware of the following: aThe boat fuel system may be different regarding use of alcohol fuelsRefer to boat owner's manualbAlcohol attracts and holds moisture which may cause corrosion of metallic parts of the fuel system Metallic and nonmetallic parts of tbe entire fuel system should be inspected frequently and replaced if signs of excessive stiffness, deterioration, corrosion, or fuel leakage are foundInspect at least annually