Cummins/Onan 3.6MKY / 4MKY — Generator Disassembly
Repair & overhaul
For the Cummins/Onan 3.6MKY / 4MKY, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 3.6MKY, Cummins/Onan 4MKY
Before you start
- Brushes will be damaged during disassembly if not held off the slip rings
- Careless handling of rotor or stator can damage winding insulation
Procedure
- Drain engine oil; remove genset from installation to a work bench.
- Remove cover from genset.
- Remove exhaust manifold-to-engine nuts and muffler-to-base screws; slide muffler right.
- Remove engine/generator-to-base mounting bolts (4).
- Disconnect leads from start relay; remove controller and start solenoid relay as assembly.
- Lift generator end and place wooden block under stator housing.
- Remove fan housing assembly from endbell.
- Secure fan; remove rotor through bolt and washer.
- Pull fan-to-shaft alignment key with magnet; remove fan with wheel puller.
- Disconnect harness leads from brush block; hold brushes off slip rings with wire.
- Disconnect starter bracket; remove endbell mounting screws, move endbell aside.
- Pull outward on rotor shaft to remove rotor.
- Remove stator wire harness connectors and stator mounting screws; pull stator straight out.
Tools required
- Lifting hoist Amazon
- Wheel puller Amazon
- Magnet Amazon
- Wooden block Amazon
- Solid round bar 7-7/8 in x 0.45 in, 9/16-12 x 1 in bolt Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Rotor through bolt torque 40-50 lb-ft
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.