1978 Johnson 175, 200, 235 HP Outboard Service Manual, Page 16Get this manual
ENGINE FUEL AND LUBRICANT TYPE OF GASOLINEUse premium or regular leaded gasoline with the following minimum octane numberPUMP POSTED OCTANE NUMBER Research Octane Number Most Commonly Used in the Past 89
IMPORT ANT: Additive compounds such as "tune-up" compounds, "tonics," "friction reducing" compounds, etc are unnecessary and are not recommendedThe use of OMC engine cleaner, OMC rust preventive oil and OMCFuel Conditioner is recommendedAbove 32 (0 C) Portable TankPour lubricant into tank, add fuelReplace filler cap securelyTo mix fuel, tip tank on Side as shown and back to upright pOSitionBuilt-in TankUse large metal filter funnelPour lubricant slowly with the fuel as tank is filledBelow 32 (0 C) Portable TankPour approximately one gallon (4 litres) gasoline into tank, add required lubricantReplace filler cap securelyThoroughly mix by shaking tankAdd balance of gasolineBuilt-in TankIn separate container mix alllubricant needed with one gallon (4 litres) or more of gasolineUse large metal filter funnelPour this mixture slowly with fuel as tank is filled