Service parts for the MMG25IF4
Grouped by system, with how many of each the parts manual calls for.
Fuel system
1 requiredOil system
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Fuel | diesel |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 26 kW |
| Standby kVA | 32 |
| Prime power | 23 kW |
| Emissions | EPA Tier F4 |
| Controller | Power Zone |
| Oil capacity | 10.4 L |
| Alternator | Marathon 283PSL1707 |
| Voltage options | 120 V, 139 V, 208 V, 220 V, 240 V, 277 V, 440 V, 480 V |
| Phase | 1 or 3 |
| Power factor | 1 (1Ø), 0.8 (3Ø) |
| Circuit breaker | 125 A |
| Battery group | 24 |
| Battery cranking | 720 CCA |
| Battery voltage | 12V V |
| Battery quantity | 1 |
| Coolant capacity | 17 L |
| Dry weight | 1102 kg |
| Wet weight | 1433 kg |
| Sound level | 66.0 dBA @ 7.0 m |
| Fuel tank | 379.0 L |
| Tank runtime | 42.9 hr |
Engine
| Oil capacity | 10.4 L |
|---|---|
| Coolant capacity | 17.0 L |
| Displacement | 2.18 L |
| Aspiration | Liquid cooled |
| Rated speed | 1800 rpm |
Same engine, other brands
3 brandsThe Isuzu 4LE2TAGV-03 in this set also powers 4 generator sets sold under 3 other brands. Service parts and maintenance intervals for the engine are shared; enclosure, alternator, controller and ratings are not.
| Brand | Models |
|---|---|
| Magnum | MLT4200IF4, MMG25IF4 |
| Isuzu | 4LE2TAGV-03 |
| John Deere | MLG20IF4 |
Maintenance & consumables
for the Isuzu 4LE2TAGV-03| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Dry type cartridge air filter | — | 250 hr | ||
| Fuel filter | Fuel filter with replaceable element | 69858 | 500 hr | Amazon eBay $21.83 NAPA $15.34 FridayParts $36.28 | |
| Oil filter | 670570304 | 1000 hr | Amazon eBay $16.89 PartsGeek $7.98 NAPA $9.09 FridayParts $20.19 | ||
| Battery | Clean Battery | — | 1000 hr | ||
| Belt | Check Fan Belt Tension (Replace If Necessary) | — | 1000 hr | ||
| Coolant | Check Coolant Level | — | 250 hr | ||
| Oil | Check Oil Level | — | 250 hr | ||
| Spark plug | Replace Air Filter Element | — | 1000 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
Service intervals
30| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Engine Oil (Isuzu) | Change | 50 hr | First service — First 50 hours (break-in period) | |
| Oil Filter Element Replacement | Replace | 500 hr | First service — Isuzu, first 50 hours and every 500 hours | |
| Engine Oil and Oil Filter (John Deere) | Change | 500 hr | 12 mo | First service — First 100 hours break-in, factory fill; do not exceed 100 hours with break-in oil |
| Check Oil Vapor Recirculation System/Non-Return Valve | Check | 250 hr | John Deere engine | |
| Engine Oil (Isuzu, MMG25IF4) | Change | 250 hr | Every 250 hours, MMG25IF4 only | |
| Change Engine Oil and Replace Oil Filter | Change | 500 hr | 12 mo | First service — John Deere; decrease to every 250 hours if not using John Deere Plus 50 II oil |
| Engine Oil (Isuzu, MMG45IF4) | Change | 500 hr | Every 500 hours, MMG45IF4 only; every 250 hours instead if harsh environment or fuel quality questioned | |
| Fuel Filter Elements (Isuzu) | Replace | 500 hr | Every 500 hours (every 250 hours if harsh environment/fuel quality questioned) | |
| Fuel Filter Elements (John Deere) | Replace | 500 hr | 12 mo | |
| Replace Engine Oil | Change | 500 hr | First service — Isuzu, every 500 hours (or every 250 hours if harsh environment/fuel quality questioned) | |
| Replace Fuel Filter Elements | Replace | 500 hr | 12 mo | John Deere engine |
| Replace Oil Vapor Recirculation Filter | Replace | 500 hr | 12 mo | John Deere engine |
| Service Battery | Other | 500 hr | 12 mo | John Deere engine |
| Water Sedimenter Element (Isuzu) | Clean | 500 hr | Every 500 hours (every 250 hours if harsh environment/fuel quality questioned) | |
| Air Cleaner Elements (John Deere) | Replace | 2000 hr | ||
| Air Filter Element (Isuzu) | Replace | 2000 hr | ||
| Alternator and Fan Belts (John Deere) | Replace | 2000 hr | ||
| Check Generator Drive Plate Torque | Check | 2000 hr | Isuzu engine | |
| Lubricate Leveling Jacks | Lubricate | 2000 hr | Isuzu engine | |
| Replace Air Cleaner Elements | Replace | 2000 hr | John Deere engine | |
| Replace Air Filter Element | Replace | 2000 hr | Isuzu engine | |
| Replace Alternator and Fan Belts | Replace | 2000 hr | John Deere engine | |
| Replace Fan Belt | Replace | 2000 hr | Isuzu engine | |
| Test Thermostats | Test | 2000 hr | John Deere engine | |
| Diesel Particulate Filter (DPF) | Other | 3000 hr | Expected service interval at least 3,000-4,500 hours depending on engine power/operating conditions; serviced by authorized provider only | |
| Exhaust Filter (DPF) Service | Other | 3000 hr | Expected service interval at least 3,000-4,500 hours based on engine power/operating conditions; serviced by authorized provider only | |
| Reset Maintenance Alarm Intervals | Other | 3000 hr | Power Zone controller maintenance alarm 3 | |
| Jack Maintenance (lubricate gearing/handle) | Lubricate | 12 mo | Perform annually | |
| Leveling Jacks | Lubricate | 12 mo | Annually | |
| Trailer Wheel Bearings Lubrication | Lubricate | 12 mo | Minimum every 12 months or 12,000 miles (19,312 km) |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Service specifications
24| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Other | Air Filter Minder Gauge Replacement Threshold | 20 | in. H2O | |
| Other | Radiator Cap Coolant Fill Clearance | 3/4 | in. | below filler neck (approx 2 cm) |
| Pressure | Loss-of-oil-pressure shutdown verification threshold | 5 | psi (34 kPa) | shut engine down immediately if pressure does not read this value within 5 seconds of restart |
| Pressure | Low Oil Pressure Shutdown Threshold | 20 | psi | |
| Pressure | Maximum trailer tire pressure | 65 | psi | |
| Pressure | Normal Operating Oil Pressure | 35-80 | psi | |
| Pressure | Oil Pressure Gauge Range | 0-100 | psi | |
| Pressure | Oil Pressure Shutdown Confirmation Threshold | 5 | psi | if not attained within 5 seconds of restart, shut engine down immediately |
| Temperature | Coolant Temperature Gauge Range | 150-250 | °F | |
| Temperature | High Coolant Temperature Shutdown Threshold | 230 | °F | |
| Temperature | High coolant temperature shutdown | 230 | °F (110°C) | stop engine immediately at or above this temperature |
| Temperature | Normal Operating Coolant Temperature | 180-200 | °F | average ambient air temperature of 70°F (21°C) |
| Torque | Generator Drive Plate Bolts | 30 | ft-lbs | |
| Torque | Generator Drive Plate Bolts | 40 | ft-lbs | |
| Torque | Generator drive plate bolts - MMG25IF4 | 30 | ft-lbs (40 Nm) | |
| Torque | Generator drive plate bolts - MMG35DF4 | 40 | ft-lbs (54 Nm) | |
| Torque | Generator drive plate bolts - MMG45IF4 | 30 | ft-lbs (40 Nm) | |
| Torque | Generator drive plate bolts - MMG55DF4 | 40 | ft-lbs (54 Nm) | |
| Torque | Trailer wheel lug nuts, first pass | 20-25 | ft-lbs (27-33 Nm) | first pass, star sequence |
| Torque | Trailer wheel lug nuts, second pass | 50-60 | ft-lbs (67-81 Nm) | second pass, star sequence |
| Torque | Trailer wheel lug nuts, third pass | 90-120 | ft-lbs (122-162 Nm) | third pass, star sequence |
| Voltage | Battery Voltage Gauge Range | 0-50 | V | |
| Voltage | Normal Battery Reading | 12-14 | V | 12 volt systems, engine running |
| Voltage | Normal Battery Reading | 24-26 | V | 24 volt systems, engine running |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Recommended fluids
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Engine oil | John Deere Plus 50 II (John Deere engine) | Refer to OEM engine manual for viscosity grade by season/climate | |||
| Fuel | Ultra-low-sulfur diesel | 379.0 L (100 gal total, 90 gal usable) |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
4Checking Generator Drive Plate Torque maintenance
- Disconnect engine starting battery
- Remove generator fan guard
- Tighten each drive plate bolt to specification in Table 4
- Install generator fan guard
- Connect battery
Resetting the Maintenance Alarms maintenance
- With unit shut down, move Control Power switch to ON
- Press any directional arrow to enter maintenance screens
- Press Enter and Stop/Reset simultaneously to open Configuration menu
- Move cursor down to Maintenance group
- Press right arrow to access sections and highlight Maintenance section
- Press right arrow to access parameters and highlight the alarm to reset
- Press Enter to select editable parameter, highlight Reset
- Press Enter to reset the selected alarm
- Repeat for additional alarms
- Press and hold Enter for five seconds to save changes
Towing the Unit - Wheel Lug Torque maintenance
Tools: Torque wrench
- Start all lug nuts by hand.
- First pass: tighten to 20-25 ft-lbs (27-33 Nm).
- Second pass: tighten to 50-60 ft-lbs (67-81 Nm).
- Third pass: tighten to 90-120 ft-lbs (122-162 Nm).
- Re-torque lug nuts in sequence after first road use.
Manual Starting of the Unit operation
⚠ Running engines produce carbon monoxide - asphyxiation hazard
- Move Control Power switch to ON
- Verify controller enters Stop mode/Home screen
- Press Engine Start button in Manual mode
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Common questions
What is the power rating of the Generac MMG25IF4?
The Generac MMG25IF4 is rated 26 kW standby (32.0 kVA).
What engine does the Generac MMG25IF4 use?
The Generac MMG25IF4 is powered by the Isuzu 4LE2TAGV-03 engine.
Is the Generac MMG25IF4 diesel or gas?
The Generac MMG25IF4 runs on diesel.
What is the oil capacity of the Generac MMG25IF4?
The Isuzu 4LE2TAGV-03 engine in the Generac MMG25IF4 has an oil capacity of 10.4 liters.
What is the coolant capacity of the Generac MMG25IF4?
The Generac MMG25IF4 cooling system holds 17 liters (4.5 US gallons) for the radiator system including the engine, per the manufacturer specification sheet.
What is the prime power rating of the Generac MMG25IF4?
The Generac MMG25IF4 is rated 23 kW prime (29 kVA), against 26 kW standby.
What is the sound level of the Generac MMG25IF4?
The Generac MMG25IF4 is rated at 66.0 dBA at 7.0 m, per the manufacturer specification sheet.
What is the dry weight of the Generac MMG25IF4?
The Generac MMG25IF4 has a dry weight of 1102 kg (2429 lb).
What size fuel tank does the Generac MMG25IF4 have?
The Generac MMG25IF4 has a 379 liter (100 US gallon) fuel tank, giving about 42.9 hours of runtime.
What voltages is the Generac MMG25IF4 available in?
The Generac MMG25IF4 is offered in 120 V, 139 V, 208 V, 220 V, 240 V, 277 V, 1 or 3-phase.
How many cold cranking amps does the Generac MMG25IF4 require?
The Generac MMG25IF4 uses 1 battery, 12V V each, 720 CCA, group 24, per the manufacturer specification sheet.
What alternator comes on the Generac MMG25IF4?
The Generac MMG25IF4 uses a Marathon 283PSL1707 alternator.
Which oil filter part number does the Generac MMG25IF4 take?
The Generac MMG25IF4 uses oil filter part number 670570304.
Which fuel filter part number does the Generac MMG25IF4 take?
The Generac MMG25IF4 uses fuel filter part number 69858.
What air filter fits the Generac MMG25IF4?
The Generac MMG25IF4 uses air filter part numbers GENERAC OE3557, GENERAC OE3656.
Troubleshooting
6Fault codes
| Code | Meaning | Remedy |
|---|---|---|
| 1049 VSCF | Overload RED Unit shuts down during operation. | Check the LEDs/Screen for alarms. Generator output is shorted or severely overloaded. Identify and clear the overload, and then restart. |
| 1051 VSCF | High Battery YELLOW LED illuminated in any state. | Check the LEDs/Screen for alarms. Voltage supply to the AVR is high. If an external battery charger is in use, contact installing dealer to correct installation. If an external battery charger is NOT in use, contact Independent Authorized Servicing Dealer. |
Symptoms & remedies
| Symptom | Remedy |
|---|---|
| Low Load indicator LED. • Indicates genset has operated at less than 30% capacity for more than 15 minutes. | Resolve by increasing electrical load. If unable to operate genset at more than 30% load, use a smaller generator. |
| Lug Door Open indicator LED. | Resolve by closing lug-box door. If condition remains unresolved, inspect lug-box door safety switch for proper operation. |
| Emergency Stop indicator LED. | Resolve by deactivating (pulling out) Emergency Stop switch. |
| Shutdown indicator LED. | Resolve by resolving shutdown condition. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Generac MMG25IF4 troubleshooting guide (33 entries) →
Repair guides
2Step-by-step procedures compiled from the Generac service manual for this model.
Parts
4| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 01035 | Central Lift Point | Central lift point | Amazon eBay | |
| 01144 | Controller | Controller | Amazon eBay | |
| 90243 | Air Filter Element | Air filter | Amazon eBay | |
| 209649 | Form: SFC626B | 1 | Service 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
| Rating | Load | L/h | gal/h |
|---|---|---|---|
| Prime | 100% | 7.8 | 2.1 |
Available documents
This page was generated from the 5 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.