F685301 Force CD UNIT (BLUE)

Always determine the cause of the engine shutdown. Make necessary repairs before attempting restarting the engine.
Air Shutoff Solenoid (If Equipped)
This optional solenoid is located on top of the engine in the air inlet system. When the solenoid is activated, the solenoid mechanically shuts off inlet air to the engine. The solenoid can only be activated by the overspeed switch or the emergency stop switch. The air shutoff must be reset before the engine can be restarted.Fuel Shutoff Solenoid
This solenoid is located on the governor or on the fuel injection pump. When the solenoid is activated, the solenoid moves the fuel rack (either directly or through the governor) to the FUEL OFF position.Overspeed Shutoffs
Magnetic pickup, (1), mounted in the flywheel housing (2).A magnetic pickup mounted in the flywheel housing senses the passage of the flywheel ring gear teeth. Should the engine speed increase above the overspeed setting of the Electronic Overspeed Switch (118 percent of rated engine speed), the magnetic pickup will sense the overspeed and send a signal to the Electronic Overspeed Switch. The Electronic Overspeed Switch activates both the air (if equipped) and fuel shutoff solenoids.The shutoffs must be reset before the engine will restart. A reset button on the Electronic Overspeed Switch (in the junction box) must be pushed to open the overspeed switch. The air shutoff lever (at the top of the air inlet housing) must be manually reset.Oil Pressure Switches
Typical example of oil pressure switches, mounted in the rear of the junction box.An oil pressure switch has wires connected to the electrical system for alarm or shutoff functions. The oil pressure switch senses oil pressure at the bearing oil gallery. If sufficient oil pressure is not achieved after engine starting, or if the engine has been running normally and then loses oil pressure, the fuel shutoff solenoid is energized to shut the engine off. No resetting procedure is required.Engine Step Oil Pressure
This is an adjustable engine speed setting that protects the engine from a failure caused by too little oil pressure for a specified speed range. This option requires two different oil pressure switches. One switch has a high pressure rating- when the engine is running above the speed setting, the engine must maintain oil pressure higher than the switch rating. The other switch has a low pressure rating- an engine running below the speed setting must maintain oil pressure above the low switch rating.In an automatic start/stop system, an automatic reset switch is used.Water Temperature Contactor Switch
The water temperature contactor switch is located in the cylinder head. High water temperature closes the switch to activate an alarm or fuel shutoff. No resetting is required. The switch opens as the coolant cools.
The sensing element must be submerged in the coolant to operate. Be sure to have an adequate water supply in the jacket water system, or engine damage could result.
Water Level Switch
Typical water level switch, mounted on the side of an expansion tank.If the coolant water level drops below the minimum level, the switch may sound an alarm, or cause a shutoff to avoid engine overheating and possible engine damage. Coolant must be added to the cooling system to clear or reset the condition.Shutoff and Alarm System Testing
Most control panels are equipped with a lamp test switch. Turn the switch to ON position to check indicator lights for proper operation. Replace defective or burnt bulbs immediately.The Engine Protective Devices shutdown controls and alarms on the engine should be tested every 1000 service hours or twice a year for proper operation by authorized, experienced service personnel.
During testing, abnormal operating conditions must be simulated. Perform the tests correctly to prevent possible damage to the engine.
Abnormal operating conditions must be simulated which could cause engine damage if the tests are performed incorrectly. Refer to the Service Manual for the testing procedures.Overspeed Switch Testing
The Electronic Overspeed Switch (if equipped) is located inside the junction box.The Electronic Overspeed Switch with Cranking Termination has a 75% VERIFY button, a RESET button, and an OVERSPEED indicator light.The Electronic Overspeed Shutoff Switch with Crank Termination has a sensing circuit which prevents the starter pinion from remaining engaged in the flywheel at excessive rpm. Crank Termination has an adjustable engine speed setting, and signals the starter motor when the engine is firing and cranking must be terminated. When the speed setting is reached, a switch opens to start the engine hour meter.After the starting motor cranks the engine, the pinion gear can remain engaged with the flywheel as the engine speed increases. When the magnetic pickup detects approximately 400 rpm (crank termination rpm), the Electronic Overspeed Switch opens the circuit to the starting motor to disengage the motor from the flywheel.The circuit will remain open until the flywheel stops. This prevents energizing the starting motor circuit again while the flywheel is turning.Your engine may be equipped with either an Overspeed Shutoff Switch or an Electronic Overspeed Switch with Cranking Termination. Both switches can be checked for proper operation at 75 percent of overspeed condition. Use the following procedure:1. Determine full load rpm from the Engine Information Plate.2. Operate the engine at or slightly above the corresponding spe