The carburettor on a Stihl 021 has three screws that adjust the settings on ... the gas and air mixture must be set properly for all three speeds. While every chainsaw comes set from the factory, you ...

Adjusting the carburetor allows you to increase or reduce the engine's idle speed, allow the right amount of fuel and air to mix in the carburetor, so tuning it properly will increase the ...

The carburettor inside most chainsaws regulates the three different engine speeds. To stop the chain from turning while idling, the idle speed screw must be reduced to decrease the flow of gas.