How long must the engines be motored before start if cold soaked?

The correct choice states that if the engines are cold soaked, they must be motored for 60 seconds before starting. This procedure is crucial because when engines are cold soaked, it means they have been exposed to very low temperatures for an extended period, which can cause oil to thicken and create additional friction in critical components during the initial start.

Motoring the engines for this duration allows the oil to circulate properly, helping to ensure that adequate lubrication is present and that all engine components are functioning smoothly before firing up the engines. This step reduces wear and tear on the engine during startup and minimizes risks associated with starting an engine that may not be sufficiently lubricated due to cold temperatures.

While other durations may be associated with different circumstances or practices, 60 seconds is the established standard under these conditions for ensuring operational reliability and engine longevity.