Facts About Generators
GeneratorsDirectoryEnginesControllersPartsManufacturersGuides
Search models or part #
Home›Generac›Generac MDG25IF4

Generac MDG25IF4 Generator Set

The Generac MDG25IF4 is a 25 kW (31 kVA) Diesel standby generator set powered by a Isuzu 4LE2TAGV08 engine. It is available at 120/240 V, 208/120 V, 240/120 V, 480/277 V and 600/346 V, 60 Hz and rated 25 A. It holds about 10.4 L (2.7 gal) of oil and 16.6 L (4.4 gal) of coolant, with a maximum ambient rating of 49 °C. Starting uses 1 battery rated 720 CCA at 12 V. The set measures 1780×890×1220 mm (70.1×35.0×48.0 in), weighs about 896 kg (1975 lb) and produces 67 dBA at 7 m. An integrated tank holds 234 L (61.8 gal), roughly 35 hours of runtime.

25 kW
Standby
2.2 L
Displacement
10.4 L
Oil capacity
2
Document types

How to read your Generac serial & model number →

Specifications

FuelDiesel
Frequency60.0 Hz
Standby power25 kW
Standby kVA31
Prime power20 kW
EmissionsTier 4 Final
ControllerElectronics DSE7310 MKII
Oil capacity10.4 L
AlternatorMarathon 282PSL1705 (4-pole, Class Class H insulation)
Voltage options120/240 V, 208/120 V, 240/120 V, 480/277 V, 600/346 V
Rated current[{'load_pct': 25, 'amps': 104}, {'load_pct': 20, 'amps': 83}, {'load_pct': 86, 'amps': 86}, {'load_pct': 70, 'amps': 70}, {'load_pct': 75, 'amps': 75}, {'load_pct': 60, 'amps': 60}] A
Power factor1.0
Circuit breaker125 A
Battery cranking720 CCA
Battery voltage12 V
Battery quantity1
Coolant capacity16.6 L
Max ambient49 °C
Dimensions (L×W×H)1780×890×1220 mm
Dry weight896 kg
Sound level67.0 dBA @ 7 m
Fuel tank234.0 L
Tank runtime35 hr

Engine

Isuzu 4LE2TAGV08
Oil capacity10.4 L
Coolant capacity16.6 L
Displacement2.2 L
AspirationTurbocharged
Rated speed1800 rpm

Maintenance & consumables

for the Isuzu 4LE2TAGV08
ItemSpecCapacityPart #Interval
Air filterS4CJ-1004E25F-004600 hr eBay PartsGeek
Fuel filter69858 Amazon eBay $42.74 PartsGeek
Oil filter5876100080500 hr PartsGeek
BeltS4CJ-1008E25F-008600 hr eBay PartsGeek
CoolantS4CJ-1007E25F-007 eBay PartsGeek
OilS4CJ-1000E25F-001600 hr eBay PartsGeek

Common questions

What is the power rating of the Generac MDG25IF4?

The Generac MDG25IF4 is rated 25 kW standby (31.0 kVA).

What engine does the Generac MDG25IF4 use?

The Generac MDG25IF4 is powered by the Isuzu 4LE2TAGV08 engine.

What fuel does the Generac MDG25IF4 use?

The Generac MDG25IF4 runs on Diesel.

What is the oil capacity of the Generac MDG25IF4?

The Isuzu 4LE2TAGV08 engine in the Generac MDG25IF4 has an oil capacity of 10.4 liters.

What alternator does the Generac MDG25IF4 use?

The Generac MDG25IF4 uses a Marathon 282PSL1705 alternator. It has 4 poles. Insulation class Class H.

Troubleshooting

7

Symptoms & remedies

SymptomRemedy
Noticeable change in engine speedShut the engine down
Loss of electrical outputShut the engine down
Equipment connected to the unit overheatsShut the engine down
Sparking occursShut the engine down
Engine misfires or there is excessive engine/gen-erator vibrationShut the engine down
Protective covers are loose or missingShut the engine down
Ambient air temperature is above 113 °F (45 °C)Shut the engine down

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

Parts

47
Part #DescriptionQtySystem
002306grease fitting and pump grease into the fitting until new grease is visible around the nozzle of the grease gun. Use only a high quality grease made specifically for lubrication of wheel bearings.BInjector PartsGeek
898027-4560Engine oil pressure sensor (for emergency stop) (Part number: ISUZU part number: 898027-4560)Sensor PartsGeek FridayParts $25.02
898071-4010Fuel air-bleeding electromagnetic pump filter-Fuel filter PartsGeek
898071-4040Gasket for fuel air-bleeding electromagnetic pump filter-Gasket PartsGeek
898074-9550Engine supply pump strainer-Strainer PartsGeek
898227-1080Controller (ECM)-Controller PartsGeek
898227-1081Controller (ECM)-Controller PartsGeek
SG09072Boost temperature / boost pressure sensorSensor PartsGeek
SG09107-1Diode module1Diode module PartsGeek
SG12022EThermal relay (Part number:46928 01500)1Thermal relay PartsGeek
SG12026ECurrent transformer (CT) (Part number:46923 04700, Specification:5VA, 100/5A)1Current transformer PartsGeek
SG12027EAmmeter (Part number:46154 16000, Specification:0－50A 50/5A)1Ammeter PartsGeek
SG12035-1Voltage adjusting resistor hand trimmerSensor PartsGeek
SG12036-1EAuxiliary receptacles2Auxreceptacle PartsGeek
SG12101-1Exciter armature winding wires1Exciter armature winding wires PartsGeek
SG12102Automatic voltage regulator (AVR) (Part number:46950 02901)1Automatic voltage regulator PartsGeek
SG12105ECircuit protector (IDEC NRF110, Rated current:4.0A)1Circuit protector PartsGeek
SG13021AVR connector1Avr connector PartsGeek
SG13061Ammeter change-over switch (Part number:46913 01000)1Ammeter change over switch PartsGeek
SG130846GFCI receptacles2Gfcireceptacle PartsGeek
SG14008Varistor1Varistor PartsGeek
SG14086-2EChecking rotary rectifier and varistorSensor PartsGeek
SG14129EFuel PipingFuelpiping PartsGeek
SG14133Fuse (10A)1Fuse PartsGeek
SG14139Electronic control fuel injection system (Common rail type) (Part number:6. Pressure limiter, 10. CKP sensor, 2. Fuel filter, 7. Injector, 11. CMP sensor, 3. Supply pump, 8. ECM, 12. Fuel tank)1Electronic control fuel injection system PartsGeek
SG14140EGR cooler (Part number:1. EGR cooler, 4. EGR valve, 2. Outlet port of coolant, 5. ECM, 3. Inlet port of coolant, 6. Boost pressure / boost temperature sensor)1Egr cooler PartsGeek
SG14141Diesel oxidation catalyst (DOC) (Exhaust IN, SEC B-B, Exhaust OUT, DOC drain)1Diesel oxidation catalyst PartsGeek
SG14142Controller (ECM) (Part number:44390 04200, Connector terminal arrangement)1Controller PartsGeek
SG14154CMP sensorSensor PartsGeek
SG14155EGR motor position sensorSensor PartsGeek
SG14156Intake manifold temperature (IMT) sensorSensor PartsGeek
000265Film of grease on the coupler will extend coupler life and eliminate squeaking.1Service part / kit PartsGeek
000393aGenerator Serial No.Service part / kit PartsGeek
000394WARNINGService part / kit PartsGeek
002832Film of grease on the coupler will extend coupler life and eliminate squeaking.1Service part / kit PartsGeek
A130889Manual-Auto selector switch3Service part / kit PartsGeek
A130923Outline Drawing (mm)Service part / kit PartsGeek
A130941Outline Drawing (in.)Service part / kit PartsGeek
A131135Outline Drawing (mm)Service part / kit PartsGeek
A131136Outline Drawing (in.)Service part / kit PartsGeek
SG09069ProtrusionsService part / kit PartsGeek
SG09070Timing chain sprocketService part / kit PartsGeek
SG12120Measurement of generator winding wire resistanceService part / kit PartsGeek
SG12121Measurement of insulation resistance of exciter armature winding wiresService part / kit PartsGeek
SG14006Measurement of insulation resistance of generator winding wiresService part / kit PartsGeek
SG14043EGenerator’s Winding Wires Resistance ValueService part / kit PartsGeek
SG14045Measurement of insulation resistance of exciter field winding wireService part / kit PartsGeek

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
Prime
Prime25%2.3
Prime50%4.21.1
Prime75%6.11.6
Prime100%7.42.0
Standby
Standby25%2.6
Standby110%8.62.3

Available documents

Spec sheet — Generac MDG25IF4-Spec-Sheet-10000024731-A (Generac)Spec sheet — mdg25if4 diesel-generator spec-sheet english (Generac)Owner's manual — mdg25if4 diesel-generator owners-manual (Generac)

Other sets with this engine

Generac MLT4200IV