Normally, the emergency diesel generator will start automatically, but for test purposes and under other conditions it may be started and operated manually. The following guidelines are for testing the operation of an air-started emergency diesel generator set.

The engine is started automatically when the ships normal supply fails and causes the solenoid air valve (located between the starting-air flask and the engine) to open, admitting starting air to the engine. The engine then turns over on air until firing begins. As the engine speed increases, the air cutoff governor valve closes and shuts off the starting air. As soon as the normal operating speed is reached and the generator develops normal voltage, the solenoid air valve also closes to shut off the starting-air supply. (The starting-air flask is charged from the high-pressure air system, through a reducing valve. The air stored in the starting-air flask varies in pressure from 300 to 600 psi, depending on the installation.) To start the engine manually, de-energize the solenoid valve. If the ships supply current is not broken, you must open the switch in the solenoid circuit. Then, admit starting air to the engine by opening the valve manually with the handwheel. After firing begins, turn the handwheel to close the valve and cut off the starting air. (The hand-wheel must be turned to the open position of the valve whenever you must leave the generator set available for emergency service.)

If the lubricating oil pressure does not build up immediately after the engine starts, shut down the engine and determine the cause of the trouble. NEVER operate the engine without lubricating oil pressure. At regular intervals, check the lube oil pressure, fuel pressure, cooling water temperature, and exhaust temperature. (In addition, clean the fuel and lubricating oil filters regularly.)

To SHUT DOWN or STOP the engine, move the fuel-control lever to the STOP position. After the lever is released, it will automatically return to the running position to permit the engine to be restarted.

OPERATING PRECAUTIONS

You must observe the following operating precautions and inspections:

1. Do NOT operate the engine without lubricating oil pressure; this will cause serious damage.

2. Do NOT operate the engine in an over-loaded or unbalanced condition. An overload condition on one or more cylinders may be indicated by an increase in the exhaust temperature or by smoky exhaust.

3. Do NOT operate the engine with an abnormal water outlet temperature.

4. Do NOT operate the engine after an unusual noise develops; the noise might be an indication of pending trouble. Investigate the noise and correct any trouble, particularly if the condition may prove harmful to the engine.

5. If the overspeed device trips and shuts down the engine, investigate the cause of the trouble before you restart the engine.

6. Make certain that the fittings of the ventilation system that serve the compartment in which the engine is located are open. If you start a diesel engine while the vent system is secured, the engine will consume the air in the compart-ment. Under these conditions, the engine may continue to operate long enough to suffocate you.

This precaution applies to installations where the engine does not have a direct air supply from the outside to the intake manifold. THESE PRECAUTIONS ALSO APPLY TO EMER-GENCY DIESEL FIRE PUMPS.