HomeGeneracGenerac MD900

Generac MD900 Generator Set

The Generac MD900 is a 900 kW (1125 kVA) Diesel standby generator set powered by a Mitsubishi S12H-Y2PTAW-1 engine. It is available at 120/208 V, 120/240 V, 277/480 V and 347/600 V, 3-phase, 60 Hz and rated 3123 A. It holds about 180 L (47.6 gal) of oil and 76 L (20.1 gal) of coolant, with a maximum ambient rating of 50 °C. Starting uses 2 group-8 batteries at 24 V. The set measures 4420×2261×2489 mm (174.0×89.0×98.0 in), weighs about 9473 kg (20884 lb) and produces 1 dBA at 1 m. An integrated tank holds 950 L (251.0 gal), roughly 12 hours of runtime. The same S12H-Y2PTAW-1 engine also powers generator sets from Kohler, Rudox Power Generation and Simson-Maxwell.

900 kW
Standby
2265.0 L
Displacement
180.0 L
Oil capacity
1
Document types

How to read your Generac serial & model number →

Typical fuel consumption for 900–905 kW Diesel generators →

Compare with other 900–905 kW Diesel generators →

Service parts for the MD900

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

Oil system

1 required

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

Specifications

FuelDiesel
Frequency60.0 Hz
Standby power900 kW
Standby kVA1125
Prime power810 kW
EmissionsTier 2
ControllerInterliGen NT Display
Oil capacity180.0 L
Alternator900kW,125°C, NEMA H (4-pole, Class H insulation)
Voltage options120/208 V, 120/240 V, 277/480 V, 347/600 V
PhaseThree-Phase
Rated current3123 A
Power factor0.8
Circuit breaker3123 A
Battery group8D
Battery voltage24 VDC V
Battery quantity2
Coolant capacity76 L
Max ambient50 °C
Dimensions (L×W×H)4420×2261×2489 mm
Dry weight9473 kg
Fuel tank950.0 L
Tank runtime12 hr

Engine

Mitsubishi S12H-Y2PTAW-1
Oil capacity200.0 L
Coolant capacity401.0 L
Displacement2265.0 L
AspirationTurbocharged, Intercooled
Rated speed1800 rpm

Maintenance & consumables

for the Mitsubishi S12H-Y2PTAW-1
ItemSpecCapacityPart #Interval
Air filterDry
Fuel filterCartridge×4200 hr
Oil filterCartridge×5GM13942 Amazon $60.99 eBay $37.99
BatteryBattery×2200 hr
BeltBelt200 hr
CoolantCoolant76.3 gal200 hr
Coolant filterUV/Ozone resistant hoses12 hr
Oil200.0 L200 hr
Spark plugSpark Plug200 hr

Common questions

How many kW is the Generac MD900?

The Generac MD900 is rated 900 kW standby (1125.0 kVA).

Which engine powers the Generac MD900?

The Generac MD900 is powered by the Mitsubishi S12H-Y2PTAW-1 engine.

Is the Generac MD900 diesel or gas?

The Generac MD900 runs on Diesel.

How much oil does the Generac MD900 take?

The Mitsubishi S12H-Y2PTAW-1 engine in the Generac MD900 has an oil capacity of 200.0 liters.

What alternator does the Generac MD900 use?

The Generac MD900 uses a 900kW,125°C, NEMA H alternator. It has 4 poles. Insulation class H.

What oil filter fits the Generac MD900?

The Generac MD900 uses oil filter part number GM13942.

Parts

16
Part #DescriptionQtySystem
0161970SBYBattery1Battery Amazon eBay
01865Fuel/Water Filtering SystemFuel filter Amazon eBay
18650Oil filter Amazon eBay $24.69
01858Engine Oil RecommendationsService part / kit Amazon eBay
01859Serial Number LocationsService part / kit Amazon eBay
01860GFCI Receptacle and Interior Light TimerService part / kit Amazon eBay
01861Component Locations - Left SideService part / kit Amazon eBay
01862Component Locations - Right SideService part / kit Amazon eBay
01863Control PanelService part / kit Amazon eBay
01864Digital ControllerService part / kit Amazon eBay
01866Parallel Setup and OperationService part / kit Amazon eBay
01867Generator Output ConnectionsService part / kit Amazon eBay
01868Voltage RegulatorService part / kit Amazon eBay
01870A299X- 68-03 fos! 104 F1035-12045 25-01 | 29 5 | F1805-10020 68-01 fo5 19Service part / kit Amazon eBay
01871Maintenance schedule and basic maintenance tasks for MCG1000MT2Service part / kit Amazon eBay
01873Maintenance schedule and extended maintenance tasks for MCG1000MT2Service 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
Standby25%92.024.3
Standby50%160.142.3
Standby75%233.261.6
Standby100%294.977.9

Available documents

Spec sheet — Generac 900kW MD900 Diesel Generator 37.1L (Generac)Spec sheet — md900-0l1427a (Generac)
Full service, cheapest listings

Priced items from this model's own parts manual.

Oil filter GM13942$37.99
1 priced item$37.99