Section 5: Troubleshooting; General Troubleshooting - Generac Mobile MMG35DF4 Owner's Manual

Section 5: Troubleshooting

General Troubleshooting

This information is intended to be a check or verification
for simple causes that can be located and fixed. It does
not cover all types of problems. See the engine operator's
Problem
Low fuel level shutdown
Low oil pressure
shutdown
Low coolant level
shutdown
High coolant
temperature shutdown
Overcrank shutdown
Overspeed or
underspeed shutdown
Owner's Manual for Mobile Generator
Possible Cause
Low fuel level
Unit not level
Fuel tank leaking
Damaged fuel sender or
wiring
Low oil level
Oil leaking from engine
Oil pressure sender
Low coolant level
Coolant hoses leaking
Engine block or water
pump leaking
Low coolant level
Blockage in radiator
Leakage in coolant hoses,
engine block, or water
pump
Fuel level low
Frequency setting incorrect
manual for additional troubleshooting information. Proce-
dures that require in-depth knowledge or skills should be
performed by a GMASD.
Check fuel level in LCD window of controller.
Confirm that unit is sitting level to ensure an accurate reading.
Check tank for leaks.
Check for continuity between sender and engine controller. (See
Wiring Diagrams
.)
Check oil level on dipstick. Add oil, if needed.
Visually inspect the engine for leaks. Restart unit and verify loss
of pressure. Shut down immediately if pressure does not reach 5
psi (34 kPa) within five seconds.
See engine operator's manual to identify corrective action.
Allow engine to cool, then check coolant level in radiator. Add
coolant, if needed.
Inspect hoses for leaks. Repair or replace as necessary.
Visually inspect for leaks. Verify no coolant has mixed with the
engine oil (oil will appear milky). See engine operator's manual for
additional information.
Add coolant if needed. Allow engine to cool, then check coolant
level in radiator. Restart engine and check coolant temperature
(on controller). Stop engine immediately if coolant temperature is
210°F (99°C) or more.
Check radiator shroud and ducting for blockage and remove any
foreign matter.
Inspect for visible leaks. Check tension of water pump serpentine
drive belt.
Remove load on generator and restart engine. Check coolant
temperature and shut engine down immediately if it starts to over-
heat (230 degrees or higher). See the engine operator's manual
for additional information on engine overheating.
Check fuel level in tank.
Check fuel pump operation.
Check air filter for blockage.
See engine operator's manual for additional information.
Disconnect all loads and restart unit. Read frequency (Hz) in the
LCD window on controller. Frequency should read 60 Hz.
If frequency is above 60 Hz, engine speed will need to be
adjusted. Contact Isuzu to adjust speed.
Solution
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