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Cummins/Onan 3100 series — Generator Disassembly

Repair & overhaul

For the Cummins/Onan 3100 series, from the Cummins/Onan service manual.

Applies to: Cummins/Onan DGBB, Cummins/Onan DGBC, Cummins/Onan DGCA, Cummins/Onan DGCB, Cummins/Onan DGCC, Cummins/Onan DGDA, Cummins/Onan DGDB, Cummins/Onan DGDK, Cummins/Onan DGEA, Cummins/Onan DGFA, Cummins/Onan DGFC

Before you start

  • Accidentally dropping the generator can damage it and cause severe personal injury and death. The hoist, straps and chains must have sufficient capacity.
  • Never withdraw the generator leaving the rotor to hang by the drive discs.
  • The rotor can be damaged if it rests on the edges of the winding slot between two poles.
  • Do not use fan blade to bar over engine.

Procedure

  1. Disconnect the line cables and conduit, marking each cable.
  2. Disconnect remote control wiring and conduit, marking each wire.
  3. Disconnect all engine wiring harness connections in the generator control and output boxes.
  4. Disconnect all generator control leads (winding taps) in the output box.
  5. If equipped, disconnect the cables to the mounted line circuit breaker.
  6. Attach hoist to output box, loosen mounting bolts and remove the box.
  7. Bar engine until one of four rotor poles points straight down so the rotor rests on the face of the pole.
  8. Attach lifting eyes and a hoist of sufficient capacity.
  9. Take up hoist slack and remove the two through bolts securing the generator to the rubber isolation mounts.
  10. Raise the generator end approximately one inch (12 mm) and securely block the engine under the flywheel housing.
  11. Remove the bolts securing the generator drive discs to the flywheel.
  12. Loosen all bolts securing the generator adapter casting to the flywheel housing; adjust hoist, remove bolts and pull the generator away.

Tools required

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Full service-parts list: Cummins/Onan DGBB →, Cummins/Onan DGBC →, Cummins/Onan DGCA →, Cummins/Onan DGCB →, Cummins/Onan DGCC →, Cummins/Onan DGDA →, Cummins/Onan DGDB →, Cummins/Onan DGEA →, Cummins/Onan DGFA →, Cummins/Onan DGFC →

Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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