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Cummins/Onan HDKAJ Generator Set

The Cummins/Onan HDKAJ is a 12.38 kW (7500 kVA) Diesel prime generator set. It is available at 120 V, 1-phase, 60 Hz and rated 62.5 A. It holds about 2.6 L (0.7 gal) of oil and 4 L (1.1 gal) of coolant. Starting uses battery rated 650 CCA at 12 V. The set measures 936×634.5×578.6 mm (36.9×25.0×22.8 in) and weighs about 191 kg (421 lb).

2.6 L
Oil capacity
4
Document types

How to read your Cummins/Onan serial & model number →

Specifications

FuelDiesel
Frequency60.0 Hz
Prime power12 kW
ControllerGenerator, Integrated Microprocessor Based Engine
Oil capacity2.6 L
Voltage options120 V
Phase1
Rated current62.5 A
Circuit breaker35 A
Battery cranking650 CCA
Battery voltage12 V
Coolant capacity4 L
Dimensions (L×W×H)936×634×578 mm
Dry weight191 kg

Filters & service parts

model family
ItemSpecCapacityPart #Interval
Air filter140-2897365 hr Amazon eBay $22.95
Fuel filter149-25138 hr Amazon eBay $36.95
Oil filter122-083350 hr Amazon eBay $25.95
Belt511-023560 hr Amazon eBay $10.00
Coolant4.0 l—10000 hr
Coolant filter— find
Oil—250 hr

Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number.

Common questions

What fuel does the Cummins/Onan HDKAJ use?

The Cummins/Onan HDKAJ runs on Diesel.

Troubleshooting

11

Fault codes

CodeMeaning
Code 1Engine Over Temperature
Code 2Low Oil Pressure
Code 3Service Check
Code 4Over Crank
Code 12Over Voltage
Code 13Under Voltage
Code 14Over Frequency
Code 15Under Frequency
Code 19Governor Actuator
Code 22Governor Actuator Overload
Code 27Voltage Sense

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Parts

10
Part #DescriptionQtySystem
541-0530Installation of Auxiliary Fuel Pump Kit on Commercial HDKAJ, HDKAK Generator Set 1 (G300)Fuel pump buy
541-0531Installation of Remote Air Cleaner Kit on Commercial HDKAJ, HDKAK Generator Set 1 (G299)Air filter buy
A043T622Recommended Spares List (RSL) for RV Generator Set (HDKAJ, HDKAK)Service part / kit buy
RSL-498Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec A)Service part / kit buy
RSL-499Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec B)Service part / kit buy
RSL-500Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec C)Service part / kit buy
RSL-501Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec D)Service part / kit buy
RSL-502Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec E)Service part / kit buy
RSL-503Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec F)Service part / kit buy
RSL-504Recommended Spares List (RSL) for RV Generator Set (HDKAJ, Spec G)Service part / kit buy

Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

RatingLoadL/hgal/h
Full-load106%0.963.63
Half-load (4000 w)53%0.490.185
No-load0.490.185

Available documents

Operator's manualReferenceParts manualService manual