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Magnum MMG120 Super Start Generator Set

The Magnum MMG120 Super Start is a 158 kW standby generator set powered by a John Deere PE4045HF285 engine. It is available at 120 V, 139 V, 208 V, 220 V, 240 V and 277 V, 3-phase, 60 Hz and rated 441 A. It holds about 14.5 L (3.8 gal) of oil and 29.8 L (7.9 gal) of coolant. Starting uses 1 group-24 battery rated 1000 CCA at 12 V. The set weighs about 2463 kg (5430 lb). An integrated tank holds 1295 L (342.1 gal), roughly 44 hours of runtime. The same PE4045HF285 engine also powers generator sets from Generac.

158 kW
Standby
4.5 L
Displacement
14.5 L
Oil capacity
1
Document types

Specifications

Frequency60.0 Hz
Standby power158 kW
Prime power144 kW
Oil capacity14.5 L
AlternatorMarathon 363PSL1607
Voltage options120 V, 139 V, 208 V, 220 V, 240 V, 277 V
Phase
Rated current441 A
Power factor1 (1Ø), 0.8 (3Ø)
Circuit breaker450 A
Battery group24
Battery cranking1000 CCA
Battery voltage12V V
Battery quantity1
Dry weight2463 kg
Fuel tank1295.0 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 Super Start?

The Magnum MMG120 Super Start is rated 158 kW standby.

What engine does the Magnum MMG120 Super Start use?

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

What is the oil capacity of the Magnum MMG120 Super Start?

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

What alternator does the Magnum MMG120 Super Start use?

The Magnum MMG120 Super Start uses a Marathon 363PSL1607 alternator.

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
Prime100%32.3
Standby
Standby100%28.0

Available documents

Service manual — MMG235 (Operation) (Magnum)