Katolight · Katolight John Deere Diesel Series

Katolight D125 (John Deere)

125 kW standby · Diesel · Liquid-cooled

Katolight D125FRJ4 125 kW diesel standby generator powered by John Deere 6068HF120. Discontinued legacy unit — specs, service info, and parts guidance.

Standby power
125 kW
Voltage options
277/480V
Frequency / Phase
60 Hz · 3-phase
Engine
John Deere 6068HF120 · 6.8L

Overview#

The Katolight D125 is a 125 kW diesel standby generator powered by a John Deere 6068HF120 engine — a 6.8-liter, six-cylinder turbocharged diesel from John Deere's widely deployed 6068 platform. This unit occupied the upper end of Katolight's John Deere Diesel Series, serving mid-range commercial buildings, schools, churches, and municipal facilities that needed more power than the four-cylinder 4045-based models could deliver.

Katolight is a discontinued brand, acquired by MTU (now Rolls-Royce Power Systems) in 2006 and rebranded as MTU Onsite Energy. No new Katolight units are manufactured, but the D125 remains one of the more commonly encountered Katolight models in the field due to its popularity in the 100-150 kW commercial standby segment. The John Deere 6068 engine has excellent parts availability through John Deere's nationwide dealer network and a deep independent aftermarket.

OnPoint provides full lifecycle support for Katolight D125 installations, from routine preventive maintenance to major engine overhauls and control system modernization. These units, properly maintained, can deliver decades of reliable standby service.

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Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

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Estimated runtime

29.6 hours(1.2 days)

Fuel consumption ≈ 6.75 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the Katolight D125 (John Deere) under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Coolant change
Every 6000 hours
Air filter
Every 1000 hours
Fuel filter
Every 500 hours
Major overhaul
20,000 hours
Load bank test
Every 12 months

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

ComponentSymptomTypical hoursSeverity
Fuel quality / degradationHard starting, filter clogging, reduced power4,380+moderate
TurbochargerPower loss, excessive smoke under load12,000+moderate
BatteryFailed to start, slow crank8,760+minor

Frequently Asked Questions

Are parts still available for the Katolight D125?
Yes. The D125 uses a John Deere 6068 engine, which has excellent parts availability through John Deere's nationwide dealer network and a deep independent aftermarket. This is one of the most commonly encountered Katolight models still in service.
What happened to the Katolight brand?
Katolight was acquired by MTU (now Rolls-Royce Power Systems) in 2006 and rebranded as MTU Onsite Energy. No new Katolight units are manufactured, but the large installed base is fully supported through aftermarket parts and independent service providers like OnPoint.

More in the Katolight John Deere Diesel Series

John Deere-powered diesel gensets from 15 to 200 kW (discontinued)

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