Cummins/Onan — Generator Assembly - Main Assembly Procedure

For these Cummins/Onan models: 4.4X, 7.7X, 8.9X, M-1641.

Applies to: Cummins Onan 8 9X, Cummins Onan M 1641

Procedure

1. Attach a sling and hoist to the rotor assembly and mount the drive disk and fan assembly to the engine flywheel.
2. Tighten the capscrews to 120 to 200 ft-lb (163 to 271 N•m).
3. Place a support under rotor and remove sling from rotor assembly.
4. Attach a sling and hoist to the stator assembly, place stator in position over free end of rotor support rod.
5. Guide the stator over rotor assembly and fasten to engine flywheel housing.
6. Tighten the stator mounting capscrews to 65 to 70 ft-lb (88 to 95 N•m).
7. Attach a sling and hoist to the end bell assembly, apply a layer of Molykote grease on end bell bearing bore.
8. Install end bell assembly, ensure rubber holding ring is not distorted, rock the end bell assembly gently into place.
9. Pull up evenly with capscrews and washers, tighten capscrews to 30 to 35 ft-lb (41 to 48 N•m).
10. Mount the generator support bracket, place shims in same position from which they were removed.
11. Tighten the mounting bolts and stud nuts to 195 to 200 ft-lb (264 to 271 N•m).
12. Install the upper and lower covers and air outlet screen onto stator assembly.
13. Using a sling and hoist, place the control cabinet onto generator stator.
14. Mount and adjust Mechanical Overspeed Switch or Magnetic Overspeed Sensor.
15. Reconnect generator output leads to load connections and all control wire leads.
16. Verify that all connections are proper and secure, then install the generator output box cover and end bell cover.
17. Connect the negative (-) battery cable and test the generator for operation.

Source: manual:943-0018 Onan UV Generator w-Torque Match-2 Regulator Service manual (10-1986).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.