Carburetors

Carburetors operate by controlling the movements to an adjustable plate called the throttle plate, which 'opens up' to allow more fuel and thus more power into the intake valve. Check out this explicative carburetor video thanks to howstuffworks.com.

• A carburetor can mix too little fuel with air - this is called a "lean" mixture. A carburetor can mix too much fuel, which is a "rich" mixture that provides a lot of power.
• A larger carburetor will allow the engine to draw in more air, if it is too big it is almost as bad as a carburetor that is too small.
• On a fuel-injected car, a throttle body that is too big will put too much gas in the combustion chamber that flows out in the exhaust unburnt.
• It is much more of a problem on a carbureted car, which will make the engine perform terribly at part throttle.
• A simple formula for calculating the proper carburetor setup is:

CFM (amount of air the engine needs) = Displacement (in cubic inches) X Maximum RPM / 3,456

Although carburetors stop being used in cars in 1990, carburetors are still used in smaller motors like motorcycles,  lawnmowers,  and chain saws. 

External Links

If you have an older car that uses a carburetor or you just want more information check out:

• HowStuffWorks - information on how a carburetor works.
• Autoguide.net - information about buying carburetors.