Lesson 1/Learning Event 1
A mixture of fuel and air is burned inside the engine cylinder during the power stroke. Mixing the fuel and
air is one of the functions of the carburetor.
The air cleaner on an internal combustion engine serves three purposes:
(1) It filters the air to remove dust and dirt before the air enters the carburetor. This is very
important because the engine requires about 9,000 gallons of clean air for every gallon of fuel it burns.
(2) It acts as a flame arrester to prevent fires in case the engine backfires.
(3) It acts as a muffler, reducing the hissing noises made by the air entering the carburetor at high
Air cleaners are generally classified as either wet or dry, depending on what method is used to filter the air.