What causes carburetor ice?

Carburetor ice primarily forms due to a steep temperature drop in the carburetor Venturi. As air flows through the narrowed passage of the Venturi, its velocity increases, which causes a decrease in pressure and a drop in temperature. This temperature drop can lead to the condensation of moisture from the air within the carburetor, especially under conditions of high humidity. Consequently, ice can form, potentially obstructing the airflow and causing engine performance issues.

The other factors mentioned, while relevant in different contexts, do not directly cause carburetor ice in the same way. High humidity contributes to the presence of moisture in the air, and excessive fuel vaporization can affect engine performance but does not inherently lead to ice formation. Low temperatures in the carburetor Venturi can influence the overall temperature conditions, but it is the steep temperature drop due to the Venturi effect that is the primary cause of carburetor ice. Understanding these dynamics is crucial for pilots and mechanics to prevent and manage carburetor icing effectively.