Which component is NOT part of a direct cranking electric starter system?

The fuel pump is not a component of a direct cranking electric starter system. A direct cranking electric starter system's primary role is to initiate the engine's operation by cranking it over, allowing it to start. The electric motor serves to provide the necessary torque to crank the engine, while the reduction gears are utilized to increase the torque output from the electric motor for effective cranking. An automatic engaging mechanism is also essential, as it ensures that the starter disengages from the engine once it has started.

In contrast, a fuel pump's primary function is to deliver fuel to the engine rather than to assist in the cranking process. The presence of a fuel pump is critical for fuel delivery systems typically, but it does not play a role in the initial starting effort of the engine in the context of a starter system. Thus, it does not belong to a direct cranking electric starter system.