To start an engine that has been routinely secured, you should first make ready the supporting systems-cooling, lubrication, and fuel-as follows:
1. Check all valves in the seawater cooling system to ensure that the system is lined up for normal operation.
2. Start the separate motor-driven seawater pump (if it is provided). If an auxiliary engine is cooled from the ship’s seawater circulating system, ensure that adequate pressure and flow will be available.
3. Vent seawater coolers, using the vent cocks or vent valves on the heat exchanger shells. (If this is not done, air or gas can accumulate, reducing the effective cooling surface area of a heat exchanger.)
4. Check the level in the freshwater expansion tank. Remember that a cold expansion tank will need a lower fluid level than one that is hot, so leave room for expansion.
5. Check the freshwater cooling system: Set all valves in their operating positions, start the motor-driven circulating pump (if it is provided), vent the system, and check the freshwater level in the expansion tank again. The freshwater level may have dropped if air or gas were vented elsewhere from the system.
6. Check the lubricating system: Check the oil level in the sump; add oil if necessary to bring it to the proper level. Ensure that adequate grease is applied to bearings that require grease lubrication. If oil sump heaters are installed, raise the lubricating oil temperature to 100°F.
7. In idle engines, the lube oil film can be lost from the cylinder walls. It is desirable for you to restore this film before you actually start the engine. (Large diesel engines will restore the film by pressurizing the lube oil system and jacking the engine over without starting it. The pressure in the lube oil system will oil the cylinders, and the pistons will distribute the oil film.) To pressurize the lubricating system, either start the motor-driven lubricating oil pump, or air-driven pre-lube pump (if installed), or operate a hand-operated lubricating oil pump. If the lubricating oil pump is driven by the engine, it will develop pressure when the engine is jacked over. To reduce the load on the jacking gear and prevent an accidental start, open any cylinder test valves or indicator cocks. Then turn the engine over using the jacking gear, which may be motor-driven or hand-operated. As the engine turns over, observe the indicator cocks for excessive moisture. The presence of excessive moisture indicates water or fuel accumulation in the cylinders.
8. When you have performed the preceding operation, disengage the jacking gear and restore the cylinder test valves or indicator cocks to their operating positions.
10. Test the alarm panel for power by manually operating such alarms as the low-pressure lubricating oil alarm and the freshwater high-temperature alarm.
11. Now start the engine with the starting system. Follow the approved written procedures for the type of starting system in use.
12. Once the engine is running, energize the low-pressure lube oil alarm and the water temperature alarm. Pay careful attention to all gauges and other indications of engine condition and performance. Diesel engines tend to be noisy, particularly when they are cold and idling. Familiarity with the normal sounds of the engine will help you avoid unnecessary panic. If the lube oil pressure does not rise immediately to the operating pressure, STOP the engine and determine the cause of the low pressure.
13. Idle the engine until the lube oil temperature reaches 100°F. Next, apply a light load of 20 to 30 percent. When the lube oil temperature reaches 120°F, apply the normal load (50 to 80 percent). If possible, avoid placing a load on the engine until the engine has reached operating temperature. Normal or high loading of a cold engine will produce carbon in the cylinder heads, cause excessive engine wear, and dilute the lubricating oil. The procedures for placing the engine “on the line” will depend on the type of installation. In general, it is best to bring the engine up to speed gradually, while being alert for symptoms of trouble when you are initially loading the engine and while the engine is approaching normal range.