USCG Exam PracticeDiesel engine principles (motor propulsion)
Before performing internal maintenance on a marine diesel engine, which combination of preparatory steps is required to ensure personnel safety?
- A. Reduce engine speed to idle, close the fuel day-tank valve, and post a watch at the throttle.
- ✓ Stop the engine, allow it to cool, isolate starting air and fuel, and engage the turning gear.Correct
- C. Stop the engine, drain the jacket-water system, and lock the throttle in the closed position.
- D. Engage the turning gear, reduce starting-air receiver pressure to zero, and open the cylinder indicator cocks.
Why B is correct
NAVEDTRA 14075 §3-1 explicitly states that before any internal work the engine is stopped, cooled, the starting air and fuel are isolated, and the turning gear is engaged so the engine cannot roll. Draining the jacket water and opening indicator cocks are not listed as required preparatory steps, and reducing to idle does not make the engine safe for internal access.
Cited:NAVEDTRA 14075 §3-1