The gasoline to oil mixture for McCulloch chainsaws is 50 to one. McCulloch recommends "Universal powered by McCulloch two-stroke oil" for all of its products with two-cycle engines.
Two-cycle engines require a mixture of oil and gasoline, which creates more emissions since oil is burned with the gas. Two-cycle oil is designed to reduce engine deposits. Two-cycle engines, also known as two-stroke engines, complete a power cycle in one crankcase revolution and have a narrower power band than four-cycle engines, which complete a power cycle in two crankcase revolutions. Two-cycle engines are found in string trimmers, outboard boat motors and motorcycles.