Question 58Motor Plants - QMED

The correct answer is D) the cylinders are not chilled by the expansion of the starting air. In a medium-speed marine propulsion engine with direct admission air starting valves, the cylinders without air starting valves fire first because they are not chilled by the expansion of the starting air. When the starting air is admitted, it expands and cools the cylinders with air starting valves, delaying their ignition. The cylinders without air starting valves, however, are not affected by this cooling effect and can fire first. The other answer choices are incorrect because: A) the operation is not under higher compression, B) fuel is admitted to all cylinders during cranking, and C) the compression is not released by opening the exhaust valve during starting.