In cars, carb icing can occasionally be a nuisance but is not usually a huge problem, as the inlet manifold and parts of the carburetor often have warm water from the cooling system or exhaust circulating through them. Motorcycles can also suffer from carb icing, although some engine designs are more prone to it than others. Air-cooled engines may be more prone to icing, though it is mostly in aircraft that the phenomenon is a significant problem.

Carb icing occurs when there is humid air, and the temperature drop in the venturi causes the water vapour to freeze. The ice will form on the surfaces of the carburetor throat, further restricting it. This may increase the venturi effect initially, but eventually restricts airflow, perhaps even causing a complete blockage of the carburetor. Icing may also cause jamming of the mechanical parts of the carburetor, such as the throttle butterfly valve.