Cummins/Onan QSB5-G2 NR3 Engine

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• Voltage does not come up to the rated voltage
  Cause: Internal problem with the generator end
  Fix: Check for even reading across the lines, if they are not this would mean you probably have a problem with the wiring of the switch or generator. If the generator voltage reads correctly, contact the TEREX service department.
• Uneven reading between the legs when applying 24 volts to the field wires
  Fix: Recheck your wiring connections. After you have the field wire connected start the unit again and check your output voltage. It may still be necessary to flash the fields to restore residual voltage.
• TROUBLE LIGHT on CONTROL PANEL is illuminated
  Cause: Broken fan belt
  Fix: Inspect fan belt and replace as needed
• No generator output voltage
  Cause: Circuit breaker tripped
  Fix: Reset circuit breaker
• Malfunction discovered
  Fix: Identify symptoms, troubleshoot, perform repair, return to service
• Low generator output voltage
  Cause: Voltage adjustment set too low
  Fix: Adjust voltage potentiometer
• Low engine speed
  Fix: Call TEREX Service
• High generator output voltage
  Cause: Voltage adjustment potentiometer set too high
  Fix: Adjust potentiometer
• High engine speed
  Fix: Call TEREX Service
• Fluctuating or surging generator output voltage
  Fix: Check engine fuel, oil, and air filters
• Fluctuating generator output voltage stability
  Cause: Load may be the cause
  Fix: Redistribute load if possible
• Engine won't crank
  Cause: Loose battery cable
  Fix: Check cables and battery electrolyte level. Recharge as necessary
• Engine shuts down
  Cause: Oil Pressure Switch not opening automatically and TROUBLE LIGHT on
  Fix: Improper coolant use a 50/50 on
• Engine runs, but loses power under load
  Cause: Clogged fuel system
  Fix: Check fuel system

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan QSB5-G2 NR3.