For McCULLOCH CS340 CS380 Chainsaw Replacement Spare Parts Carburetor Carb Assembly . The carburetor automatically adjusts the appropriate amount of fuel according to the needs of different working conditions of the engine to save fuel. The main function of the carburetor is to mix air and gasoline in the correct ratio to keep the engine working properly. We provide clear pictures and take measurements where possible. Please check as many times as possible to make sure the item is what you need. Easy to install and remove, no complicated operations required, saving time and effort.