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Magnum MMG120 Generator Set

The Magnum MMG120 is a 91 kW (91 kVA) diesel standby generator set powered by a John Deere PE4045HF285 engine. It is available at 120/240 V, 120/208 V and 277/480 V, single/three-phase and 60 Hz. It holds about 13.7 L (3.6 gal) of oil and 29.8 L (7.9 gal) of coolant, with a maximum ambient rating of 48.89 °C. Starting uses battery rated 1000 CCA. The set measures 3350×1270×1950 mm (131.9×50.0×76.8 in), weighs about 2463 kg (5430 lb) and produces 68 dBA at 7.01 m. An integrated tank holds 1294.6 L (342.0 gal), roughly 44 hours of runtime. The same PE4045HF285 engine also powers generator sets from Generac.

91 kW
Standby
4.5 L
Displacement
13.7 L
Oil capacity
2
Document types

Specifications

Fueldiesel
Frequency60.0 Hz
Standby power91 kW
Standby kVA91
Prime power85 kW
EmissionsTier III
ControllerMicroprocessor-based controller
Oil capacity13.7 L
Voltage options120/240 V, 120/208 V, 277/480 V
Phasesingle/three
Battery cranking1000 CCA
Max ambient48.89 °C
Dimensions (L×W×H)3350×1270×1950 mm
Dry weight2463 kg
Sound level68.0 dBA @ 7.01 m
Fuel tank1294.6 L
Tank runtime44 hr

Engine

John Deere PE4045HF285
Oil capacity13.7 L
Coolant capacity29.8 L
Displacement4.5 L
Aspirationturbocharged
Rated speed1800 rpm

Maintenance & consumables

for the John Deere PE4045HF285
ItemSpecCapacityPart #Interval
Air filter find
Fuel filter find
Oil filter find
Belt find
Coolant
Coolant filter find
Oil

Common questions

What is the power rating of the Magnum MMG120?

The Magnum MMG120 is rated 91 kW standby (91.0 kVA).

What engine does the Magnum MMG120 use?

The Magnum MMG120 is powered by the John Deere PE4045HF285 engine.

What fuel does the Magnum MMG120 use?

The Magnum MMG120 runs on diesel.

What is the oil capacity of the Magnum MMG120?

The John Deere PE4045HF285 engine in the Magnum MMG120 has an oil capacity of 13.7 liters.

Troubleshooting

8

Fault codes

CodeMeaning
SDSensor fail (FLS)
WRNWarning (WRN)

Symptoms & remedies

SymptomCauseRemedy
LOW FUEL LEVEL SHUT DOWNFuel level on the Liquid Crystal Display (LCD) window is low or fuel tank has leaks.Check the fuel level and ensure it is not running dry. Check for leaks in the fuel tank.
LOW OIL PRESSURE SHUT DOWNEngine oil pressure is less than 20 psi (138 kPa).Check engine oil level and add oil if required. Visually inspect the engine for oil leaks.
LOW COOLANT LEVEL SHUT DOWNCoolant level in the radiator is low or coolant lines have visible leaks.Check the coolant level and add coolant if necessary. Inspect for leaks in coolant hoses, engine block, and water pump.
HIGH COOLANT TEMPERATURE SHUT DOWNCoolant temperature is 230°F (110°C) or more.Check coolant level in the overflow jug and add coolant if necessary. Inspect radiator, coolant hoses, engine block, water pump for leaks. Check serpentine drive belt tension.
OVERCRANK SHUT DOWNEngine will not start.Check fuel level in tank and proper operation of the fuel pump. Check air filter for blockage.
OVERSPEED OR UNDERSPEED SHUT DOWNEngine speed is above or below 60.0 Hz.Disconnect all loads and restart the generator to read frequency (Hz). Adjust engine speed as necessary.

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

Parts

6
Part #DescriptionQtySystem
100-001Air Filter1Air filter PartsGeek dieselpartscenter $75.38
PP88S12Pump PP88S121Pump PartsGeek
01615Enclosure PanelsService part / kit PartsGeek
01616Unit Decals - Left Side - MMG120Service part / kit PartsGeek
23597Decal, Panel Light Switch (Optional)Service part / kit PartsGeek
30176Decal, Flex - Tier III Battery ChargerService part / kit PartsGeek FridayParts $109.99

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
Prime65.8
Prime50%14.03.7
Prime75%21.25.6
Prime100%28.07.4
Standby
Standby100%28.0

Available documents

Spec sheet — MMG120 Mobile (Magnum)Service manual — MMG235 (Operation) (Magnum)