Low Coolant Level Shutdown; High Coolant Temperature Shutdown; Overcrank Shutdown; Overspeed/Underspeed Shutdown - Magnum MMG25FHZ Operating Manual

LOW COOLANT LEVEL SHUTDOWN

1. Allow the engine to cool.
2. Check the coolant level in the radiator. Remove the radiator cap and add coolant until it is 3/4" below
the filler neck. Secure the radiator cap back into its original position.
3. Inspect coolant hoses, engine block and water pump for visible leaks.

HIGH COOLANT TEMPERATURE SHUTDOWN

4. Check the coolant level in the overflow jug.
5. Restart the engine and read the coolant temperature to verify High Coolant Temperature Shutdown.
Stop the engine immediately if the coolant temperature is 230°F or more.
6. Allow the engine to cool. Add coolant to the overflow jug if it is low and then check the level of coolant
in the radiator. Remove the radiator cap and add coolant until it is 3/4" below the filler neck. Secure the
radiator cap back into its original position.
7. Check the radiator shroud and ducting for blockage and remove any foreign matter.
8. Inspect coolant hoses, engine block and water pump for visible leaks.
9. Check the tension of the serpentine drive belt for the water pump.
10. Check the coolant temperature sender on the engine block and the connecting wiring for damage. To
check for continuity between the sender and the engine controller, remove the bolts at the top and bottom
of the control panel and open the panel like a door. Consult the appropriate DC wiring diagram on page
41 for the proper path between the engine controller and the temperature sender.
11. If the sender and wiring are good and no other problems are found, remove the load on the generator
and restart the engine. Observe the coolant temperature and shut the engine down immediately if it
starts to overheat. Consult the ENGINE OPERATION AND MAINTENANCE MANUAL for additional
information on engine overheating.

OVERCRANK SHUTDOWN

1. Check the fuel level in tank.
2. Check for proper operation of the fuel pump.
3. Check air filter for blockage.
4. If the engine will not start, consult the ENGINE OPERATION AND MAINTENANCE MANUAL for
additional information on troubleshooting starting problems.
OVERSPEED OR UNDERSPEED SHUTDOWN
1. Disconnect all loads and restart the generator. Read the frequency (Hz) on the LCD display. With no
loads on the generator, the frequency should read 60.0 Hz.
2. If the frequency is above or below 60.0 Hz, the engine speed will have to be adjusted. See the engine
manual for throttle adjustments on mechanical governed units and see the electronic governor manual
for electronically controlled units.
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