What must follow the maximum dry motoring time for the first engine?

The maximum dry motoring time for the first engine is crucial for preventing overheating and ensuring the longevity of engine components. After this period, a cool-down time is mandated. The correct answer indicates that a 5 minutes cool-down is required following the maximum dry motoring time.

This 5 minutes allows the engine components to dissipate heat that has accumulated during the motoring process. Proper cooling is vital in maintaining engine integrity and performance, as excessive heat can lead to damage or degradation of parts. The selected duration of cool-down is a standard recommendation found in operational guidelines, ensuring that engines remain within safe temperature ranges.

Other durations for cool-down, such as 10, 15, or 2 minutes, do not align with the specified protocols for engine maintenance and operation. Excessively long cool-down intervals could unnecessarily delay operations, while too short intervals may not effectively manage heat, leading to increased risk of engine wear or failure. Thus, the 5 minutes cool-down is both efficient and protective for the first engine after dry motoring.