The engine of chainsaw
Chainsaw engines are traditionally either a two-stroke gasoline (petrol)internal combustion engine (usually with a cylinder volume of 30 to 120 cm3) or an electric motor driven by a battery or electric power cord. Combustion engines today (2016) are supplied through a traditional carburetor or an electronically adjustable carburetor.
The traditional carburetor needs to be adjusted, i. e. when operating in high or low altitudes, or their fuel oil-to-gasoline ratios must be adjusted to run properly. Electrically influenced carburetors make all adjustments automatically. These systems are provided by most large chain saw producers. Husqvarna calls its "Autotune," and it is commonly standard on most saws of the 5XX saw series.
To reduce user fatigue problems, traditional carburetors can be de-vibrated (protected from vibrations) or they can be heated as well. Many saws offer a Winter and Summer mode of operation. Winter mode applies in temperatures below 0 °C / 32 °F where inside the cover a hole is opened leaving warm air to the air filter and carburetor to prevent icing. In warmer environment the hole is closed and both units are not ventilated with warm air.
To ensure clean air supply to the carburetor, chainsaw producers offer different filters with fine or less fine mesh. In clean surrounding air a less fine filter can be used, in dusty environment the other. The fine filter keeps the air clean to its optimum (i.e. 44 µm) but has the tendency to clog. This leads to the engine dying.
The engines are designed so that they may be operated in different positions, upside-down or tilted 90 degrees.