Carburation, fuel and mixture

(Airframe, engines and systems: carburation, fuel and mixture)

The engine burns a mixture of petrol vapour and air, and something has to meter the right amount of fuel into the airflow at every power setting. In most light aircraft that something is a float carburettor, a beautifully simple device with one dangerous habit: it can ice up and quietly throttle the engine on a mild, damp day. Understand the carburettor and you understand both how to lean the mixture and why carburettor heat exists.