Kohler · REOZ Series (Diesel Commercial Standby)

Kohler 80REOZJ4

85 kW standby / 76 kW prime · Diesel · Liquid-cooled

80 kW Tier 4 Final diesel commercial standby generator. John Deere-powered diesel with EPA Tier 4 Final emissions compliance for commercial and institutional applications.

Kohler Kohler 80REOZJ4 generator — specifications and details
Standby power
85 kW / 76 kW prime
Voltage options
120/208V, 277/480V, 120/240V
Frequency / Phase
60 Hz · 1/3-phase
Engine
John Deere 4045HFG04 · 4.5L
EPA / Emissions
Tier 4 Final
CommercialHealthcareGovernment
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Overview#

The Kohler 80REOZJ4 is an 80-kilowatt EPA Tier 4 Final diesel commercial standby generator powered by a John Deere engine at 1800 RPM. It is certified for both stationary emergency and non-emergency applications and features a brushless rare-earth permanent-magnet alternator with Fast-Response excitation, sustained short-circuit capability up to 300% for 10 seconds, a durable sound-attenuating steel housing rated at 71 dB(A) at 7 meters, and integrated environmental containment.

Our service experience#

OnPoint services John Deere-powered Kohler diesel generators across Northern California. The 80REOZJ4 shares the REOZJ platform with the 100REOZJF and 125REOZJG, giving us strong parts commonality and technician expertise across the mid-range diesel lineup.

Engineering specifications

Physical

Length
116.1 in
Width
44.1 in
Height
84.9 in
Wet weight
5,605 lb

Acoustic

Sound @ 7m, full load
71 dBA
Enclosure
Sound-attenuated

Fuel system & runtime

Integral fuel tank
192 gal
Fuel use @ full load
6.4 GPH
Fuel use @ 75% load
4.8 GPH

Photos

Kohler 80REOZJ4 — product photo

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Kohler 80REOZJ4

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

Estimate runtime on this tank

Estimated runtime

38.9 hours(1.6 days)

Fuel consumption ≈ 4.94 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 Kohler 80REOZJ4 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 250 hours or 12 months
Coolant change
Every 3000 hours
Air filter
Every 500 hours
Fuel filter
Every 500 hours
Major overhaul
≈ 15,000 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
DEF system (SCR catalyst)Derate warning, NOx fault, DEF quality alert4,380+moderate
Fuel quality / degradationInjector fouling, hard starting, filter clogging4,380+moderate
TurbochargerPower loss, excessive smoke under load12,000+moderate
Battery (starting)Failed to start, slow crank8,760+minor

Frequently Asked Questions

What engine is in the Kohler 80REOZJ4?
The 80REOZJ4 uses a John Deere diesel engine, turbocharged and aftercooled, rated at 1800 RPM with EPA Tier 4 Final emissions certification.
What is the sound level of the 80REOZJ4?
Per Kohler specifications, the 80REOZJ4 is rated at 71 dB(A) at 7 meters at full load with the sound-attenuating steel housing.
Does the 80REOZJ4 include environmental containment?
Yes. The unit includes a 125% environmental containment basin for oil/coolant and a UL 142 listed subbase fuel tank for 24-hour runtime at prime rating.

Compatible equipment

Engine

Transfer switches

More in the REOZ Series (Diesel Commercial Standby)

Kohler's diesel commercial standby series — 10 to 510 kW, John Deere and Kohler engines, built for life-safety loads.

View all 33models in this series →

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