Section 5 - Troubleshooting; Problems And Solutions - Generac Power Systems MGG155 Operating Manual

Problems and Solutions

Some of the more common problems are listed in the table below. This information is intended to be a check or
verification that simple causes can be located and fixed. It does not cover all types of problems. Procedures that
require in-depth knowledge or skills (like flashing the field) should be referred to an authorized service department.
Problem
Engine Cranks But Will
Not Start
Engine Will Not Crank
(Electric Start)
Engine Starts But Will
Not Run Smoothly
Engine Overheats
No Output Voltage
High Output Voltage
Low Output Voltage
Electrical Shock When
Frame Is Touched
Mechanical Noise
35319 C

Section 5 - Troubleshooting

Table 5 - General Troubleshooting Guide
Possible Cause
No fuel.
Low oil level.
Restricted air flow.
No spark.
Dead battery.
Emergency stop is acti-
vated.
Fuel or ignition problem.
Excessive load.
Debris or dirt buildup on
engine/radiator.
Circuit breaker tripped or
failed.
Internal failure of alterna-
tor.
Idle switch on.
Excessive speed.
Wrong speed.
Static charge.
Grounded armature or field
coil.
Internal failure of alterna-
tor.
Loose flexplate.
Engine fan or belts issues.
MGG155/210 Operating Manual
Solution
Check that fuel valves are open.
Low Oil Pressure Shutdown activated. Replenish oil to full.
Check/replace air filter.
Check/replace spark plug(s).
Remove batteries and trickle charge. Never jump start. Even if
only one battery is bad, it is recommended that both batteries be
replaced at the same time.
Reset controller after an emergency stop.
See OEM engine manual. Contact Generac Mobile Products
Technical Support.
Remove one or more electrical loads.
Remove debris. Clean engine surfaces to allow cooling.
Reset circuit breaker or replace if required.
Check electrical connections.
Contact Generac Mobile Products Technical Support.
Turn idle switch OFF.
Check engine for malfunction. Verify engine RPM.
Check AVR adjustment.
Check engine for malfunction. Verify engine RPM.
Check AVR adjustment.
Ground unit frame at local reference ground.
Contact service.
Contact service.
Tighten flexplate to flywheel and alternator shaft.
Contact Generac Mobile Products Technical Support.
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