Carburetor Basics

The basic function of a carburetor on a spark ignition engine is to mix the fuel with the incoming air in the proper proportions so that the engine can then burn it efficiently. All of the small engines carburetors control the speed and the load of the engine.

There are three basic elements of a carburetor:

  • fuel bowl

  • venturi

  • jets

Fuel bowl keeps the amount of fuel inside the carburetor at a constant level. 

Venturi is a short tube with a tapering constriction in the middle that causes an increase in the velocity of the air flow and a corresponding decrease in fluid pressure. This pressure is used to draw the fuel from the bowl into the air flow stream of the carburetor.