What is the first action to take if you experience an engine fire during startup?

When an engine fire occurs during startup, the primary concern is to limit the fuel flow to the engine to help extinguish the fire as quickly as possible. The option to continue cranking the engine (which is incorrect as the correct course of action should not involve continuing cranking) indicates an action that might lead to a sustained fuel supply that can exacerbate the fire condition.

However, the recommended first action in the event of an engine fire during startup is indeed pulling the mixture to the idle cut-off position. This action effectively shuts off fuel to the engine, thereby reducing the possibility of further fuel combustion and helping to extinguish the flames. Following this, the fuel shutoff valve should be turned off to eliminate fuel supply completely.

Understanding the order of operations in emergency procedures is crucial. Immediate actions should aim to minimize any potential danger posed by fuel combustion. Other choices such as throttling the engine up would fuel the fire, and continuing to crank would not only continue to supply fuel but could potentially allow ignition of any accumulated fuel vapors.