This means that for every 40 parts of gasoline, you should add 1 part of 2-cycle oil.
For example, if you are filling up a 1-gallon gas can, you would add 1 ounce of 2-cycle oil.
It's important to mix the fuel and oil thoroughly before using the chain saw. You can do this by shaking the gas can vigorously for several minutes.
Always use fresh fuel in your chain saw. Old fuel can gum up the carburetor and cause the chain saw to run poorly.
If you are not going to be using the chain saw for a while, it's a good idea to drain the fuel tank and carburetor to prevent the fuel from evaporating and leaving behind deposits.
