3406 MARINE ENGINE Automatic Start-Stop Caterpillar

Automatic Start-Stop
1.1. Conditions Required For Starting
2.1. Protection Devices
3.2. Batteries
4.2. Overcranking:
5.2. Engine Operation
6.2. Shutting Down
7.2. Engine Exerciser

An automatic start-stop system is used when an engine must start when a specific condition occurs. With no one in attendance, the engine will start, increase speed, pick-up the load, operate the load until a second condition occurs, remove the load, cool and stop.

Conditions Required For Starting

1. Either the ambient (engine room) temperature should be maintained at a minimum temperature of approximately 70°F (20°C); or, the engine jacket water temperature must be maintained at a minimum temperature of 90°F (32°C). A jacket water heater should be used to maintain this temperature.
2. If a prelube oil pump is used, the pump must operate before the starting motor(s) are energized, and stop when the engine starts and oil pressure increases.

Protection Devices

The engine's control panel may be equipped with protection devices to protect the engine while cranking, operating and stopping.


Lights can indicate if a fault has occurred in the battery charging system causing the battery to be either undercharged or overcharged.


A timer allows the engine to crank either once for 30 seconds, or to crank through 5 ten-second cranking cycles (depending upon the device used) while unattended. If the engine does not start before the time elapsed, the fuel system will be shut off and a light will indicate a starting failure.

Engine Operation

Audible prealarms provide an audible and usually a visual indication for low oil pressure, high water temperature, low fuel supply or low jacket water temperature before the condition becomes critical. These alarms are self resetting as soon as the condition is corrected.

The engine may also be equipped with shutoff devices so that if low oil pressure, high jacket water temperature or an engine overspeed condition occurs, the engine will be shut down and a corresponding light will indicate the cause of the shutdown. These devices must be reset after repairs have been made and before starting. See the topic, EMERGENCY SHUTOFF DEVICES AND ALARMS.

If your engine is equipped with an electric set, the control panel should be equipped with an ammeter, a frequency meter and a voltmeter to indicate the load being supplied. Depending upon the type of oepration, the panel may be equipped with other meters and lights. Know these instruments and their normal readings. They will indicate how the engine is performing.

Shutting Down

A timer allows the engine to remove or to transfer the load, and to continue running for up to 2 minutes to allow the engine to cool before stopping.

Engine Exerciser

At preset times, the exerciser will start, run and stop the engine in order to ensure both proper lubrication of all engine parts and proper equipment operation if and when the standby unit is needed.

Be familiar with all instructions included with the equipment.