Cummins/Onan — Vibration Isolators Installation and Adjustment

Installation

From a Cummins/Onan service manual — check it applies to your exact model before use.

Applies to: Cummins/Onan DFHA, Cummins/Onan DFHB, Cummins/Onan DFHC, Cummins/Onan DFHD, Cummins/Onan QST30 engine

Procedure

1. Place the vibration isolators on the genset support structure.
2. Shim or grout so all isolator bases are within 0.25 inch (6 mm) elevation of each other on a flat, level surface.
3. Loosen the side snubber lock nuts so the top plate is free to move; align top plate with base and springs.
4. Place the genset onto the isolators, aligning the skid mounting with the threaded isolator hole.
5. Insert leveling bolt through the skid into the isolator to adjust clearance between top plate and isolator base.
6. Achieve nominal clearance of 0.25 inch (6 mm) or greater for rocking during startup and shutdown.
7. Adjust the leveling bolts until the set is level with roughly equal clearance on all isolators, then lock the leveling bolt with the lock nut.
8. Snubber nuts may remain loose to provide better isolation between genset and support structure.

Full service-parts list: Cummins/Onan DFHA →, Cummins/Onan DFHB →, Cummins/Onan DFHC →, Cummins/Onan DFHD →

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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