CRANKSHAFT AS 4P2974 - Caterpillar

All Caterpillar Industrial, Marine And Generator Set Engines Equipped With An Electrical Shutoff SystemThere are several components in an engine electrical system that will continue to draw small amounts of current when the engine is not running. These include the time delay relay, the speed switch and the charging alternator. An unused engine that has all three of these components can discharge its batteries in less than a month.
Low ambient temperature will decrease battery efficiency and compound this problem.
In applications where the engine is not used for extended periods, and where a battery charger is not used, use a battery disconnect switch to eliminate this problem. By installing the 7N718 Battery Disconnect Switch and 8H8648 Instruction Film between the negative terminal of the battery and the negative terminal of the starting motor, the electrical circuit can be broken without disconnecting the negative battery cable. A suitable bracket should be fabricated to mount the switch close to either the battery or the starting motor. The 2W8685 Junction Box Group can be used on generator set engines to mount the battery disconnect switch. In all applications the 7N718 Battery Disconnect Switch should be mounted within 30° of vertical.