FAA Powerplant Written Practice Test

What does pre-oiling an engine help to ensure before starting?

1. Engine ignition

2. Reduced wear on engine components

3. Correct fuel-air mixture

4. Propeller alignment

The correct answer is: Reduced wear on engine components

Pre-oiling an engine is a crucial procedure that helps to reduce wear on engine components before starting the engine. When an engine has been sitting idle, the oil that lubricates its internal parts can drain away from critical areas, leaving components unprotected from metal-to-metal contact upon initial start-up. By pre-oiling, oil is circulated through the engine using a manual or electric pump, ensuring that vital areas such as bearings, journals, and camshaft lobes are coated with lubricant. This pre-lubrication reduces the friction that occurs during the first moments of engine operation, which is when wear is most likely to happen. Proper lubrication helps to maintain component integrity, prolonging the engine's life and improving reliability. Therefore, pre-oiling is a preventative measure intended to protect the engine's internal parts, ensuring that they are adequately lubricated and reducing the risk of damage during initial operation.