Type of Oil

• All Toro single stage snow throwers require the same type of oil. The oil used is called two-cycle engine oil. It's the type of oil designed for smaller engines. Toro recommends using Use Toro 50:1 2-Cycle Oil or an equivalent high-grade, certified two-cycle oil.
  
  

Putting Oil In

• Oil for the Toro S120 must be mixed with gasoline prior to operating the snow thrower. Single-stage snow throwers require a 50:1 ratio of gasoline to engine oil. Add one-half gallon of gasoline in an approved fuel container followed by 1.3 ounces of two-cycle oil. Cover the container and mix it thoroughly. This mixture is then added to the snow thrower. This must be done every time the engine needs gas. Oil is added no other time to the snow thrower.
  
  

Where To Buy

• Two-cycle oil is not hard to find. In fact, most auto parts stores carry this type of oil. The point of purchase for your snow thrower is another place that will likely sell two-cycle oil. Various online vendors sell it as well. Prices for two-cycle oil as of 2011 averaged around $3 for a 16-ounce bottle.
  
  

What Not to Use

• Toro makes it clear in their service manual that under no circumstances is it permissible to use standard engine oil like the type used in your motor vehicle. Do not mix the gasoline and oil at an incorrect ratio either. These can both cause serious engine damage.