Cummins/Onan — Removing And Disassembling The Generator
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- The generator is heavy. You will need an assistant and a hoist of sufficient capacity.
- Accidentally dropping the generator can damage it and cause severe personal injury and death.
- Disconnect starting battery cables (negative [-] first) before starting.
- Always disconnect a battery charger from its AC source before disconnecting the battery cables.
Procedure
- Disconnect line cables and conduit, marking each cable.
- Disconnect remote control wiring and conduit, marking each wire.
- Disconnect all engine wiring harness connections in generator control and output boxes.
- Disconnect all generator control leads (winding taps) from output box.
- If equipped, disconnect cables to mounted line circuit breaker.
- Remove B1 lead from tapped adjustable resistor in generator air outlet opening.
- Remove stator-through-stud nuts, end bell, and stator assembly.
- Remove air baffle from adapter.
- Support rotor with hoist and sling.
- Loosen rotor-through-stud nut and turn out until nut is at end of shaft.
- Strike nut sharp blow while pulling rotor outward to loosen from tapered shaft fit.
- Raise generator end approximately one inch (12 mm) and securely block engine under flywheel housing.
- Lower generator slightly so blocks carry most of weight.
- Wipe clean and visually inspect all parts.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 19-21 SinoCMP $119.00 ft-lbs (26-28 N·m) torque for stator through-studs
- 55-60 ft-lbs (75-81 N·m) torque for rotor-through-stud nut
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.