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Cummins/Onan GN550-DG-A3 Engine

The Cummins/Onan GN550-DG-A3 is a 0.06 L naturally_aspirated engine rated at 3000 rpm. It powers generator sets from Cummins/Onan, including the K400 and K450.

Also known as: Onan GN550-DG-A3

0.055 L
Displacement
3000 rpm
Rated speed
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Engine specifications

Displacement0.055 L
Aspirationnaturally_aspirated
Rated speed3000 rpm

Common problems

7
  • Only slight output voltage is delivered (3 ~ 6V)
    Cause: Worn brush or faulty contact surface of slip ring
    Fix: Clean brush contact and slip ring, or replace brush
  • Rated output voltage is not available
    Cause: Abnormal load circuit, blown circuit breaker (S.T.D., voltage 10%)
    Fix: Remove abnormality in load circuit and replace fuse
  • Pilot lamp does not light and output voltage is OV
    Cause: Faulty contact of receptacles or disconnected wiring inside of control box
    Fix: Repair or replace
  • Output voltage is not delivered
    Cause: Disconnected wiring
    Fix: Repair or replace stator coil, demagnetization of permanent magnet, clean brush contact and slip ring, repair or replace brush, or repair or replace sub coil
  • Output voltage is more than S.T.D. voltage by 30%
    Cause: Defective AVR
    Fix: Replace
  • Output voltage OV
    Fix: Set the switch to the desired AC or DC position
  • Fluctuation of engine revolution is abnormal
    Cause: Disconnected or punctured AVR capacitor, faulty brush contact, excessive initial current, low engine output, faulty engine governor
    Fix: Replace capacitor, check for wear, wear amount, and contamination of contacting surface of brush and clean if necessary, repair or replace

Compiled from service & troubleshooting documentation across every generator set that uses the Cummins/Onan GN550-DG-A3.

Maintenance schedule

ItemSpecCapacityPart #Interval
Air filterFoam wrapper + cartridge element; clean/re-oil foam each service, replace cartridge every 6 cleanings or yearly.—25 hr
Fuel filterFuel filter/cock cleaning per periodic maintenance chart; no cartridge part number given.—
OilAPI SE/SF class engine oil; 10W-30 below -10C, SAE#20 below 15C, SAE#30 above 15C. First change at 10 hrs, then every 50 hrs.—50 hr
Spark plugGap 0.6-0.7mm (GS130/GS280 engines), 0.7mm (K1400/K3000), 1.0mm (K2100/GN1850), 0.7mm (K1800), varies by model.—50 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Common questions

What is the displacement of the Cummins/Onan GN550-DG-A3?

The Cummins/Onan GN550-DG-A3 has a displacement of 0.055 liters.

Which generators use the Cummins/Onan GN550-DG-A3 engine?

The Cummins/Onan GN550-DG-A3 powers 2 generator set(s), including Cummins/Onan K400, Cummins/Onan K450.

How often should you change the oil in the Cummins/Onan GN550-DG-A3?

The Cummins/Onan GN550-DG-A3 oil change interval is every 50 hours.

What is a common problem with the Cummins/Onan GN550-DG-A3 engine?

A commonly reported issue on generators using the Cummins/Onan GN550-DG-A3 is: Only slight output voltage is delivered (3 ~ 6V). Cause: Worn brush or faulty contact surface of slip ring. Fix: Clean brush contact and slip ring, or replace brush.