How Chain Saws Work

Here is the right side cover plate for the saw:

When you remove the cover plate, you expose the centrifugal clutch:

You can also see the spark arrestor and the spark plug:

Also visible is one end of the gas tank.

On the other side of the engine you find the pull-cord and the air intakes:

In the above photo, the air intake to the left of the pull-cord handle supplies cooling air to the engine, and the two smaller intakes to the right of the pull-cord handle supply air for the carburetor. Removing the plate covering the carb reveals a paper air filter, and then the choke plate and the carb's venturi.