1987 Johnson/Evinrude CU Outboards 35A thru 55 Service Manual, Page 45Get this manual
Fuel Requirements
Minimum Octane Models Recommendations Any automotive gasoline or gasoline with no more than 10 EthanolAny automotive gasoline or gasoline with no more than 10 EthanolPump Posted 67 "RON"
45 Comm 55 Comm35,40,48,50