Section 5 - Troubleshooting; General Troubleshooting - Generac Power Systems MAGNUM MMG75D Operating Manual

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 manual for additional troubleshooting information. Procedures
that require in-depth knowledge or skills should be referred to a trained technician.
Problem
Low Fuel Level
Shutdown
Low Oil Pressure
Shutdown
Low Coolant Level
Shutdown
High Coolant
Temperature Shutdown
Overcrank Shutdown
Overspeed or
Underspeed Shutdown
33701 C

Section 5 - Troubleshooting

Table 6 - General Troubleshooting Guide
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
MMG75D-100D Operating Manual
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
DC Wiring
.)
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 John Deere to adjust speed.
Solution
43