How to Pre-mix Gas & Oil for Outboard Engines

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Two-stroke engines have enjoyed popularity with boat owners since Ole Evinrude devised the first outboard motor in 1911. Many modern two-stroke outboard manufacturers use an oil reservoir and a metered oil-injection system to make the 50-to-1 mix of gasoline-to-oil, but on their smaller outboards, you make the mix by hand.

Plan Ahead

One 6-ounce can of two-stroke oil treats three gallons of gas, so do a bit of arithmetic before you hit the pump. Divide the number of gallons of fuel you plan to take on by three. If you plan to add 12 gallons of gas to your boat's tank, divide twelve by three and you get four. Use a one-gallon gas can to mix all the oil you'll add to the tank. Pour four 6-ounce cans of oil into the one-gallon gas can and top it off with gas. Slosh it around to mix it, add it to your boat's gas tank and add 11 gallons -- remember, you've already added the first gallon of gas with the oil -- of gas to the tank. Voila! Your boat's two-stroke gas-oil mixture is ready to go boating.