Question 251Motor Plants - Assistant Engineer

The correct answer is D) small diesel engines utilizing electric starting equipment. Glow plugs are used to assist in the starting of small diesel engines, typically those found in boats and other marine applications that utilize electric starting rather than a manual crank. Glow plugs help to preheat the air in the engine's cylinders, making it easier for the engine to start, especially in cold weather conditions. This is in contrast to larger, direct-drive diesel engines (option A), diesel engines designed for residual fuels (option B), and medium-speed, four-stroke cycle diesel engines (option C), which generally do not require glow plugs to start.