Cummins/Onan LS-15M — HC4-7 Axial Alignment Procedure
Adjustments · Generator to engine alignment
For the Cummins/Onan LS-15M, from the Cummins/Onan service manual.
Applies to: Cummins/Onan DFAA, Cummins/Onan DFAB, Cummins/Onan DFAC, Cummins/Onan DFBF, Cummins/Onan DFCB, Cummins/Onan DFCC, Cummins/Onan DFCE, Cummins/Onan DFE
Procedure
- Check only when an objectionable vibration is present.
- Fasten dial indicator holding device to skid base, engine block, or generator shell with magnetic base or clamp.
- Position sensor point on the generator shaft hub.
- Bar the engine over in a clockwise rotation as viewed from engine flywheel through a couple of rotations.
- Record indicator readings in eight equally spaced points around the shaft diameter.
- Remove the capscrews connecting drive discs and flywheel and mark discs and flywheel.
- Rotate engine or generator so drive disc holes are repositioned 180 degrees from original location.
- Put capscrews back in and retorque. Recheck shaft alignment.
- If runout unchanged, rotate discs to 30, 60 or 90 degrees from original location.
- If T.I.R. does not improve, inspect flywheel pilot and drive disc runouts.
Tools required
- Dial indicator with magnetic base or clamp Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Optimal T.I.R. for runout is .000 inch
- Recommendation to reduce measured T.I.R. runout by one half
Full service-parts list: Cummins/Onan DFBF →, Cummins/Onan DFCC →, Cummins/Onan DFCE →, Cummins/Onan DFE →
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.