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Home›Generac›Generac MLT4080

Generac MLT4080 Generator Set

The Generac MLT4080 is a 9.8 kW (13.1 kVA) standby generator set powered by a Mitsubishi L3E-W461ML engine. It is available at 120/240 V, 3-phase, 60 Hz and rated 50 A. It holds about 5.4 L (1.4 gal) of oil and 4.5 L (1.2 gal) of coolant. Starting uses 1 group-24 battery rated 440 CCA at 12 V. The set measures 170×70×30 mm (6.7×2.8×1.2 in) and weighs about 1695 kg (3737 lb). An integrated tank holds 114 L (30.1 gal), roughly 64 hours of runtime. The same L3E-W461ML engine also powers generator sets from Magnum and Mitsubishi.

9 kW
Standby
1.0 L
Displacement
5.4 L
Oil capacity
1
Document types

How to read your Generac serial & model number →

Specifications

Frequency60.0 Hz
Standby power9 kW
Standby kVA13
Prime power8 kW
Emissions4F
Oil capacity5.4 L
AlternatorMarathon 201CSA5411
Voltage options120/240 V
Phase3 ph.
Rated current50 A
Power factor.8PF
Circuit breaker30 A
Battery group24
Battery cranking440 CCA
Battery voltage12V V
Battery quantity1
Dimensions (L×W×H)170×70×30 mm
Dry weight1695 kg
Fuel tank114.0 L
Tank runtime64 hr

Engine

Mitsubishi L3E-W461ML
Oil capacity3.6 L
Coolant capacity4.5 L
Displacement1.0 L
Aspirationnaturally aspirated
Rated speed1800 rpm

Maintenance & consumables

for the Mitsubishi L3E-W461ML
ItemSpecCapacityPart #Interval
Air filter—1000 hr find
Fuel filter—1000 hr find
Oil filterChange the engine oil and filter after the first 50 hours of operation, then every 250 hours.893020250 hr PartsGeek
BeltFan Belt—1000 hr find
Coolant—12000 hr
Coolant filter—250 hr find
OilAPI Grade6.7 qt—1200 hr

Common questions

What is the power rating of the Generac MLT4080?

The Generac MLT4080 is rated 9 kW standby (13.1 kVA).

What engine does the Generac MLT4080 use?

The Generac MLT4080 is powered by the Mitsubishi L3E-W461ML engine.

What is the oil capacity of the Generac MLT4080?

The Mitsubishi L3E-W461ML engine in the Generac MLT4080 has an oil capacity of 3.6 liters.

What alternator does the Generac MLT4080 use?

The Generac MLT4080 uses a Marathon 201CSA5411 alternator.

Troubleshooting

20

Symptoms & remedies

SymptomCauseRemedy
Low oil pressure shutdownLow oil levelVerify oil level on dipstick. Add oil, if needed.
Oil leaking from engineVisually inspect the engine for leaks.
Oil pressure switch failureRefer to OEM engine operator’s manual to identify corrective action.
High coolant temperature shutdownLow coolant levelAdd coolant if needed. Allow engine to cool, then check coolant level in radiator. Restart engine and check coolant temperature. Stop engine immediately if coolant temperature is 210°F (99°C) or more.
Leakage in coolant hoses, engine block, or water pumpInspect for visible leaks. Verify tension of water pump serpentine drive belt.
Unit cranks, but will not startFuel level lowCheck fuel level in tank. Verify fuel pump operation.
Overspeed or Underspeed ShutdownFrequency setting incorrectDisconnect all loads and restart unit. Read frequency (Hz) in the LCD window on controller. Frequency should read 60 Hz. If frequency is above 60 Hz, engine speed will need to be adjusted. Refer to the engine operator’s manual for throttle adjustment information.
Mast Lights Off, but Ballast Indicators on Control Panel are OnLight fixture is too hotAllow light to cool 10-15 minutes before restarting.
Mast Lights Off, and Ballast Indicators on the Control Panel are OffGenerator output incorrect. Low transformer output.Check the connections inside the control box and inside each ballast box. Check the incoming voltage to the ballast by checking the available voltage on the GFCI receptacle. Incoming voltage should be 120V +/- 5V. If voltage is incorrect, the engine speed may need to be adjusted or generator may require service.
Mast Lights On But the Light Output is LowFixture and/or lens is dirtyClean reflective surface inside fixture and both inside and outside surface of glass lens. Use mild soap and water to clean lens. Other chemicals may have an adverse effect on the glass.
Fuel Tank - Drain WaterDrain Water From Fuel Tank
Belt And Belt Tension - Inspect And AdjustInspect And Adjust Belt And Belt Tension
Air Cleaner Element - Clean, Check And ReplaceClean, Check And Replace Air Cleaner Element
Fuel System - Bleed AirBleed Air From Fuel System
Water Sedimenter - Drain WaterDrain Water From Water Sediment Separator
Blockage in radiatorInspect radiator shroud and ducting for blockage and remove any foreign matter.
Restricted air filterInspect air filter for blockage. Refer to OEM engine operator’s manual for additional information.
Mast lights OFF, ballast indicators ONLight fixture is too hot Faulty lamp connection Lamp broken Loose lighting connections Damaged or loose electrical cordAllow light to cool 10-15 minutes before restarting. Check that the lamp is tight in the socket. Check for broken arc tube or outer lamp jacket, broken or loose components in lamp envelope, or blackening/deposits inside tube. Check the connections inside the mast junction box and each mast light housing/socket. Check the mast electrical cord for damage and check the cord connections inside the control box.
Mast lights OFF, ballast indicators OFFLoose lighting connections Generator output incorrect Low transformer outputCheck the connections inside the control box and inside each ballast box. Check the incoming voltage to the ballast by checking the available voltage on the GFCI receptacle. Incoming voltage should be 120V ±5V. If voltage is incorrect, the engine speed may need to be adjusted or generator may require service. The voltage from the transformer should read approximately 400VAC as the light “strikes” (induces an arc), then drop and slowly rise back up to stabilize at 240-260VAC. On hard wired models, remove the mast junction box cover and insert the wire probes into the connector blocks for the light and ground. If proper voltage is not achieved, perform capacitor check to determine if the capacitor or coil needs to be replaced.
Mast lights ON, low light outputFixture and/or lens is dirty Lamp worn due to normal use Damaged or loose electrical connections Generator output incorrect Low transformer outputClean reflective surface inside fixture and both inside and outside surface of glass lens. Use mild soap and water to clean lens. Other chemicals may have an adverse effect on the glass. Replace lamp. Check the mast coil cord, mast junction box and mast light connections. Check the incoming voltage to the ballast. Incoming voltage should be 120V ±5V. If the voltage is incorrect, the engine speed may need to be adjusted or the generator may require service. The voltage from the transformer should read approximately 400VAC as the light “strikes” (induces an arc), then drop and slowly rise back up to stabilize at 240-260VAC. On hard wired models, remove the mast junction box cover and insert the wire probes into the connector blocks for the light and ground. If proper voltage is not achieved, perform capacitor check to determine if the capacitor or coil needs to be replaced.

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

Parts

64
Part #DescriptionQtySystem
00120BeltBelt PartsGeek
00147CONTROL POWER SWITCHControl power switch PartsGeek
00161WING NUTWing nut PartsGeek
00202GLOW PLUGGlow plug PartsGeek
00203GLOW PLUGGlow plug PartsGeek
003574Quick Disconnect Fittings for the LightsQuick disconnect fittings PartsGeek
003791GLOW PLUG OFF1Glow plug PartsGeek
003793GLOW PLUG1Glow plug PartsGeek
004478GLOW PLUG INDICATOR, RUN, START, GLOW PLUG A, B, C2Spark plug PartsGeek
004481Wheel LugWheel lug PartsGeek
004548Glow Plug Indicator1Glow plug PartsGeek
11199Seal, axle bearing2Seal PartsGeek
12227Hose, oil drain .375 X 20, 30R71Hose PartsGeek
12441Cable, battery - 31.5" 4GA blk (for batt disc. opt.)1Cable PartsGeek dieselpartscenter $2.61
12442Cable, battery - 58.5" 2GA blk (for batt disc. opt.)1Cable PartsGeek
13876Kit, heater - fuel filter1Fuel filter PartsGeek
60777Clamp, hose - .312 fuel hose crimp style1Hose PartsGeek
65649Heater, engine - low rad hose1Hose PartsGeek
000277WARNING: Burn hazard. Never operate lights with a damaged or missing lens cover.Service part / kit PartsGeek
002306needle nose applicator1Service part / kit PartsGeek
00232Towing Unit - Step 10Service part / kit PartsGeek
00243GreaseService part / kit PartsGeek
00246Safety alert symbol; used to alert you to potential personal injury hazards.Service part / kit PartsGeek
00325FUEL FILLER LOCATION (under door): Use clean DIESEL FUEL ONLY.Service part / kit PartsGeek
00326STOP EMERGENCY STOP SWITCH: For emergency shutdown; stops engine and trips main circuit breaker.Service part / kit PartsGeek
00327DETAIL C: For emergency shutdown; stops engine and trips main circuit breaker.Service part / kit PartsGeek
00328DETAIL D: For emergency shutdown; stops engine and trips main circuit breaker.Service part / kit PartsGeek
003754WARNING: Burn hazard. Lamps become extremely hot while in use. Allow 10–15 minutes for cooling before handling or lowering mast. Touching a hot lens or fixture can cause severe burns.Service part / kit PartsGeek
003792RUN START1Service part / kit PartsGeek
003794RUN START1Service part / kit PartsGeek
004477400W Flagger Station Switches2Service part / kit PartsGeek
004480grease capService part / kit PartsGeek
004490WARNING: Burn hazard. Lamps become extremely hot while in use. Allow 10–15 minutes for cooling before handling or lowering mast. Touching a hot lens or fixture can cause severe burns.Service part / kit PartsGeek
004550WARNING: Burn hazard. Lamps become extremely hot while in use. Allow 10–15 minutes for cooling before handling or lowering mast. Touching a hot lens or fixture can cause severe burns.1Service part / kit PartsGeek
004553VIN Tag1Service part / kit PartsGeek
004558Winch Assembly2Service part / kit PartsGeek
004559CAUTION1Service part / kit PartsGeek
004561Unit ID Tag1Service part / kit PartsGeek
00768Mast Junction Box Wiring and Light Connections1Service part / kit PartsGeek
02076Unit ID Tag, Vin TagService part / kit PartsGeek
11253Cap, grease - axis with rubber plug 3500#2Service part / kit PartsGeek
11254Plug, grease cap - for zerk (Axis)2Service part / kit PartsGeek
11275Decal, Magnum logo w/ web - red vinyl1Service part / kit PartsGeek atldiesel $28.53
11277U-bolt, axle4Service part / kit PartsGeek
11278Tie plate, spring2Service part / kit PartsGeek FridayParts $5489.60
11279Nut, locking8Service part / kit PartsGeek
11280Spring, axle2Service part / kit PartsGeek
11555BWeldment, removable tongue - 74"1Service part / kit PartsGeek
12140Decal set, common mast 4-lang1Service part / kit PartsGeek kuduparts $8.00
12141Decal set, LT eng/safety 4-lang1Service part / kit PartsGeek
12207Axle, 3500 lb. 56SC 68.5TC1Service part / kit PartsGeek
12262Decal, 4000/5000 set up 4-lang (manual winch)1Service part / kit PartsGeek
12880Decal, instruction 4000/5000 4-lang (electric winch)1Service part / kit PartsGeek
12881Decal, instruction 3000 4-lang (EW)1Service part / kit PartsGeek
13614Decal, mast junction box wiring - 4 light (for units with 2, 3 & 5 pos. locking terminal blocks)1Service part / kit PartsGeek dieselpartscenter $0.58
15540Wheel, P205X75R15 radial w/rim2Service part / kit PartsGeek
15546Oil heater, pan - magnetic1Service part / kit PartsGeek
15547Blanket, battery for 24 series1Service part / kit PartsGeek
209649Form: SFC626B1Service part / kit PartsGeek
36431SERVICE LOGService part / kit PartsGeek
40954Bearing, axle (inner)2Service part / kit PartsGeek
60096Lug Nut, .500-20 (incl. w/axle)10Service part / kit PartsGeek
60674Wheel stud, axle10Service part / kit PartsGeek
60766Valve, drain 18MM-1.5 w/nipple1Service 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
Standby

Available documents

Owner's manual — 10000045518 (Generac)Owner's manual — 10454 (Generac)

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