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Magnum MMG25IF4 Generator Set

The Magnum MMG25IF4 is a 26 kW (36 kVA) standby generator set powered by a Isuzu 4LE2TAGV-03 engine. It operates at 60 Hz. It holds about 10.4 L (2.7 gal) of oil and 17 L (4.5 gal) of coolant. The same 4LE2TAGV-03 engine also powers generator sets from Generac, Isuzu and John Deere.

26 kW
Standby
2.18 L
Displacement
10.4 L
Oil capacity
0
Document types

Service parts for the MMG25IF4

Grouped by system, with how many of each the parts manual calls for.

Fuel system

1 required

Oil system

1 required

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

Frequency60.0 Hz
Standby power26 kW
Standby kVA36
Prime power23 kW
Emissions4f
ControllerPower Zone
Oil capacity10.4 L
AlternatorMarathon 283PSL1707,285PSL1700

Engine

Isuzu 4LE2TAGV-03
Oil capacity10.4 L
Coolant capacity17.0 L
Displacement2.18 L
AspirationLiquid cooled
Rated speed1800 rpm

Same engine, other brands

3 brands

The Isuzu 4LE2TAGV-03 in this set also powers 6 generator sets sold under 3 other brands. Service parts and maintenance intervals for the engine are shared; enclosure, alternator, controller and ratings are not.

BrandModels
GeneracMDG20IF4-MLG20IF4, MLG20IF4, MLT4200IF4, MMG25IF4
Isuzu4LE2TAGV-03
John DeereMLG20IF4

Maintenance & consumables

for the Isuzu 4LE2TAGV-03
ItemSpecCapacityPart #Interval
Air filterDry type cartridge air filter250 hr
Fuel filterFuel filter with replaceable element69858500 hr Amazon $21.83 eBay $21.83 FridayParts $36.28
Oil filter6705703041000 hr Amazon eBay $16.89 PartsGeek $7.98 FridayParts $20.19
BatteryClean Battery1000 hr
BeltCheck Fan Belt Tension (Replace If Necessary)1000 hr
CoolantCheck Coolant Level250 hr
OilCheck Oil Level250 hr
Spark plugReplace Air Filter Element1000 hr

Compatible filters for the Isuzu 4LE2TAGV-03 — cross-referenced via Donaldson. Options to verify against your serial number, not confirmed for this exact unit.

  • Air filter: Generac OE3557 Generac OE3656 Isuzu 8972319000 Isuzu 5864014350 Isuzu 8972599390

Common questions

What is the power rating of the Magnum MMG25IF4?

The Magnum MMG25IF4 is rated 26 kW standby (36.0 kVA).

Which engine powers the Magnum MMG25IF4?

The Magnum MMG25IF4 is powered by the Isuzu 4LE2TAGV-03 engine.

What is the oil capacity of the Magnum MMG25IF4?

The Isuzu 4LE2TAGV-03 engine in the Magnum MMG25IF4 has an oil capacity of 10.4 liters.

How much coolant does the Magnum MMG25IF4 hold?

The Magnum MMG25IF4 cooling system holds 17 liters (4.5 US gallons) for the engine, per the manufacturer specification sheet.

What is the continuous rating of the Magnum MMG25IF4?

The Magnum MMG25IF4 is rated 23 kW prime (29 kVA), against 26 kW standby.

Which alternator is fitted to the Magnum MMG25IF4?

The Magnum MMG25IF4 uses a Marathon 283PSL1707,285PSL1700 alternator.

What oil filter fits the Magnum MMG25IF4?

The Magnum MMG25IF4 uses oil filter part number 670570304.

What fuel filter does the Magnum MMG25IF4 use?

The Magnum MMG25IF4 uses fuel filter part number 69858.

What air filter fits the Magnum MMG25IF4?

The Magnum MMG25IF4 uses air filter part numbers GENERAC OE3557, GENERAC OE3656.

Troubleshooting

6

Symptoms & remedies

SymptomRemedy
LOW FUEL LEVEL SHUTDOWN1. Check the fuel level on the LCD window. Confirm that the unit is sitting level to ensure an accurate reading. 2. Check for leaks in the fuel tank. The engine controller will shut the engine down when there is five percent of fuel remaining in the tank. This is done to keep the fuel lines from running dry. 3. If the fuel level is good and no leaks are found, check the fuel level sender and the connecting wiring for damage. To check for continuity between the sender and the engine controller, remove the appropriate bolts from the control panel to access the inside of the control box. Refer to the DC wiring diagram in the back of this manual for the proper path between the engine controller and the fuel level sender.
LOW OIL PRESSURE SHUTDOWN1. Check the level of the engine oil with the dipstick. The engine controller will shut the engine down when the oil pressure is less than 15 psi (103 kPa). Add oil if required. 2. Visually inspect the engine for oil leaks. 3. If the oil level is good, restart the unit and verify the loss of oil pressure. Shut the engine down immediately if the oil pressure value does not read 5 psi (34 kPa) within five seconds. 4. Check the oil pressure sender. To identify corrective action, refer to the troubleshooting section of the engine operator’s manual provided with the unit.
LOW COOLANT LEVEL SHUTDOWN1. Allow the engine to cool. 2. Check the coolant level in the radiator. To access the radiator cap, you must remove the access panel from the top of the enclosure directly above the radiator. Add coolant until it is 3/4 in. (1.9 cm) below the filler neck. Secure the radiator cap back into its original position. 3. Inspect coolant hoses, engine block and water pump for visible leaks. 4. Check engine oil to verify no coolant has mixed with it (oil will appear milky if coolant is present). Refer to the engine operator’s manual for additional information.
HIGH COOLANT TEMPERATURE SHUTDOWN1. Check the coolant level in the overflow jug. 2. Restart the engine and read the coolant temperature to verify a high coolant temperature shutdown. Stop the engine immediately if the coolant temperature is 210°F (99°C) or more. 3. Allow the engine to cool. Add coolant to the overflow jug if it is low and then check the level of coolant in the radiator. To access the radiator cap, you must remove the access panel from the top of the enclosure directly above the radiator. Add coolant until it is 3/4 in. (1.9 cm) below the filler neck. Secure the radiator cap back into its original position. 4. Check the radiator shroud and ducting for blockage and remove any foreign matter. 5. Inspect coolant hoses, engine block and water pump for visible leaks. 6. Check the tension of the serpentine drive belt for the water pump. 7. If no other problems are found, remove the load on the generator and restart the engine. Check the coolant temperature and shut the engine down immediately if it starts to overheat. Refer to the engine operator’s manual for additional information on engine overheating.
OVERCRANK SHUTDOWN1. Check the fuel level in the tank. 2. Check for proper operation of the fuel pump. 3. Check the air filter for blockage. 4. If the engine will not start, refer to the engine operator’s manual for additional information on trouble-shooting starting problems.
OVERSPEED OR UNDERSPEED SHUTDOWN1. Disconnect all loads and restart the generator. Read the frequency (Hz) on the LCD window. With no loads on the generator, the frequency should read 60.0 Hz. 2. If the frequency is above or below 60.0 Hz, the engine speed will have to be adjusted. Refer to the engine operator’s manual for throttle adjustments on mechanically governed units and refer to the electronic governor manual for electronically controlled units.

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

Parts

4
Part #DescriptionQtySystem
01035Central Lift PointCentral lift point Amazon eBay
01144ControllerController Amazon eBay
90243Air Filter ElementAir filter Amazon eBay
209649Form: SFC626B1Service part / kit Amazon eBay

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
Prime47.3212.5

Available documents

Full service, cheapest listings

Priced items from this model's own parts manual.

Fuel filter 69858$21.83
Oil filter 670570304$7.98
2 priced items$29.81