Cummins/Onan — Returning a Unit to Service
Maintenance · Generating set
From a Cummins/Onan owner's manual covering: 25.0 DEH-515R, 25.0 DEH-53R, 30.0 DEH-15R, 30.0 DEH-3R, 30.0 DEH-9XR. Check it applies to your exact model before use.
Applies to: Cummins/Onan 25.0 DEH-515R, Cummins/Onan 25.0 DEH-53R, Cummins/Onan 30.0 DEH-15R, Cummins/Onan 30.0 DEH-3R, Cummins/Onan 30.0 DEH-9XR, Ford 2711E engine
Before you start
- Do not smoke while servicing batteries. Explosive gases are emitted.
Procedure
- Remove cover and protective wrapping; remove plug from exhaust outlet.
- Check oil warning tag and verify oil viscosity is correct for ambient temperature.
- Clean and check battery; measure specific gravity (1.260 at 77 F) and verify level.
- Check coolant level and adjust if necessary.
- Connect batteries.
- Verify no loads are connected to generator.
- Start engine.
- After start, apply load to at least 50 percent of rated capacity and check gauges.
Tools required
- Hydrometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Specific gravity 1.260 at 77 F (25 C)
Full service-parts list: Cummins/Onan 25.0 DEH-515R →, Cummins/Onan 25.0 DEH-53R →, Cummins/Onan 30.0 DEH-15R →, Cummins/Onan 30.0 DEH-3R →, Cummins/Onan 30.0 DEH-9XR →
Source: Cummins/Onan owner's 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.