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Cummins/Onan 6.3 NHEL / 6.5 NH — Generator Disassembly

Repair & overhaul

For the Cummins/Onan 6.3 NHEL / 6.5 NH, from the Cummins/Onan service manual.

Applies to: Cummins/Onan NHEL

Before you start

  • The brushes will be damaged during disassembly if not held off the slip rings.
  • Careless handling of the stator can damage the insulation on the stator windings. Do not brush the stator windings against the rotor as it is lifted clear.

Procedure

  1. Drain the engine oil while the generator set is still mounted in the vehicle.
  2. Remove the generator set from the vehicle and place it on a sturdy work bench.
  3. Remove the flywheel guard and the noise shield.
  4. Remove the carburetor and intake manifold assembly to provide clearance.
  5. Disconnect lead wires from charge resistor, low oil pressure cutoff switch, and B+ terminal on ignition coil.
  6. Remove brush block cover and disconnect B+ (outboard) and B- (inboard) lead wires.
  7. Pull each brush outward and insert a stiff wire to hold brushes off the slip rings.
  8. Remove the transformer cover and (LP gas) disconnect fuel line at vaporizer coupling.
  9. Attach special lifting plate and hoist; lift the set until vertical and resting on the scroll.
  10. Remove capscrew and two EIT lock washers securing ground strap to drip pan.
  11. Remove three vibration isolator center screws and lift away from drip pan.
  12. Remove the four capscrews, lock washers, and nuts securing stator housing to engine-to-generator adapter.
  13. Install puller on end of stator housing and tighten center screw until housing lifts free of rotor and end bearing.
  14. Carefully lift the stator assembly straight up until it clears the rotor.
  15. Remove the rotor through-bolt, install rotor tool, and loosen rotor from crankshaft.

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 NHEL →

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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