If the main air bleed of a float-type carburetor becomes clogged, how will the engine run?

In a float-type carburetor, the main air bleed plays a critical role in the mixing of air and fuel for proper combustion. When this passage becomes clogged, it disrupts the air supply that combines with the fuel. As a result, the engine receives less air than required for optimal performance.

Due to the lack of sufficient airflow, the mixture of fuel becomes overly saturated. This condition causes the engine to run rich, characterized by an excess of fuel relative to air in the combustion chamber. A rich mixture can lead to issues such as rough idling, decreased performance, and increased emissions, as the engine cannot burn all the fuel efficiently.

Therefore, when the main air bleed is clogged, the engine’s running condition will indeed be rich, which aligns with the correct answer.