Kinja reply

At its most basic a carburetor is just a venturi, or a tube with a narrow bit in the middle.

Air moving through the narrow section has to move faster to cram the same volume through a smaller space, this causes the pressure to drop (low pressure= suction). This sucks fuel through the jet just like drinking through a straw. This air / fuel mix then goes into the cylinder and is ignited by the spark plug to create pure happiness. As for the rest of the diagram below, the float meters in fuel to the float bowl just like the float in your toilet tank. Use the fuel in the bowl and the float goes down which opens the needle valve and lets in more fuel. If these floats sink the bowls become overfilled and ‘flood’ the carb.