Question 421General Subjects - Assistant Engineer

The correct answer is B) Movement of the main piston through the steam cylinder. The position of the pilot slide valve in a reciprocating pump is controlled by the movement of the main piston through the steam cylinder. As the piston moves, it actuates the pilot slide valve, which in turn controls the admission and exhaust of steam to the pump's cylinders. This allows the pump to operate and deliver the desired flow. The other options are incorrect because they do not directly control the position of the pilot slide valve. Adjusting the tappet collars, moving the tappets, or the stay rods may affect the pump's operation, but they do not specifically regulate the pilot slide valve position.