What fuel system component purges the fuel from the engine when the engine is shut down?

• A. Boost Pump
• B. Overspeed Drain Valve (ODV)
• C. Fuel Drain Valve
• D. Vent Valve

Answer: (B)

When you shut the engine down, residual fuel in the engine fuel lines and manifold needs to be cleared to prevent pooling and fire risk. The overspeed drain valve is designed to do exactly that: it opens to purge the remaining fuel from the engine system and directs it away from the engine. This automatic purge helps ensure a clean shutdown and reduces the chance of fuel remaining in the engine after shutdown.

The boost pump’s role is to supply fuel pressure for starting and normal operation, not to purge fuel on shutdown. The fuel drain valve can purge fuel, but its use is not the automatic shutdown purge feature described here. The vent valve handles venting and pressure equalization, not purging fuel from the engine.