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Home›Generac›Generac QT025

Generac QT025 Generator Set

The Generac QT025 is a 25 kW Natural gas, propane vapor standby generator set powered by a Generac 1.6L engine. It is available at 120/240 V and 120/208 V, 1Ø or 3Ø, 60 Hz and rated 104 A. It holds about 3.8 L (1.0 gal) of oil and 7.6 L (2.0 gal) of coolant, with a maximum ambient rating of 50 °C. Starting uses 1 group-26 battery rated 525 CCA at 12 V. The set produces 72 dBA at 7 m.

25 kW
Standby
1.6 L
Displacement
3.8 L
Oil capacity
2
Document types

How to read your Generac serial & model number →

Typical fuel consumption for 25–30 kW Bi-Fuel (NG/LP) generators →

Compare with other 25–30 kW Bi-Fuel (NG/LP) generators →

On this pageService partsSpecsEngineMaintenanceFuel consumptionDocumentsFAQ

Service parts for the QT025

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

Air intake

1 required
59402Air filter$18.00eBay

Oil system

1 required
244-A4531Oil filtersee priceAmazon

Belts

1 required
199-A4531Belt$89.99eBay

Ignition

1 required
275-A4531Spark plug$22.57eBay

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

Specifications

FuelNatural gas, propane vapor
Frequency60.0 Hz
Standby power25 kW
EmissionsEPA
ControllerH-100, Nexus, Nexus Digital, R-100
Oil capacity3.8 L
Voltage options120/240 V, 120/208 V
Phase1Ø or 3Ø
Rated current104 A
Power factor1.0
Circuit breaker125 A
Battery group26
Battery cranking525 CCA
Battery voltage12 V
Battery quantity1
Coolant capacity7.6 L
Max ambient50 °C
Sound level72.0 dBA @ 7 m

Engine

Generac 1.6L
Oil capacity4.26 L
Coolant capacity8.5 L
Displacement1.6 L
AspirationNaturally Aspirated
Rated speed3600 rpm

Maintenance & consumables

for the Generac 1.6L
ItemSpecCapacityPart #Interval
Air filter59402500 hr Amazon eBay $18.00
Fuel filter—50 hr
Oil filter244-A4531150 hr Amazon eBay
BatteryGroup 26, 525CCA—100 hr
BeltValve Timing199-A4531 Amazon eBay $89.99
Coolant8.5—
Coolant filter—
Oil4 Quarts4.5 Quarts—150 hr
Spark plug275-A4531 Amazon eBay $22.57

Common questions

What is the power rating of the Generac QT025?

The Generac QT025 is rated 25 kW standby.

Which engine powers the Generac QT025?

The Generac QT025 is powered by the Generac 1.6L engine.

What kind of fuel does the Generac QT025 run on?

The Generac QT025 runs on Natural gas, propane vapor.

How much oil does the Generac QT025 take?

The Generac 1.6L engine in the Generac QT025 has an oil capacity of 4.26 liters.

What oil filter does the Generac QT025 use?

The Generac QT025 uses oil filter part number 244-A4531.

Which air filter part number does the Generac QT025 take?

The Generac QT025 uses air filter part number 59402.

Parts

112
Part #DescriptionQtySystem
100-A4531Gasket kit, Engine Overhaul1Gasket Amazon eBay
101-A4531Gasket kit, Engine Overhaul, Upper1Gasket Amazon eBay
103-A4531Gasket, Rocker Cover1Gasket Amazon eBay $53.89
104-A4531Gasket, PCV Valve1Gasket Amazon eBay
110-A4531Gasket, Engine Oil Filler Cap1Gasket Amazon eBay
113-A4531Gasket, Cylinder Head1Gasket Amazon eBay
118-97390VALVE COVER GASKET1Gasket Amazon eBay
122-A4531Oil Seal, Camshaft1Seal Amazon eBay $29.26
126-97390CAMSHAFT HOUSING GASKET1Gasket Amazon eBay
135-97390FRONT WATER JACKET COVER GASKET1Gasket Amazon eBay
135-A4531Gasket, Fuel Pump Hole Cover1Gasket Amazon eBay
139-97390FRONT MAIN OIL SEAL RETAINER GASKET1Gasket Amazon eBay
143-97390FRONT MAIN OIL SEAL1Seal Amazon eBay
145-97390CAMSHAFT OIL SEAL1Seal Amazon eBay
146-A4531Gasket, Rear Oil Seal Case1Gasket Amazon eBay
148-97390OIL PUMP DRIVE SHAFT SEAL RETAINER GASKET1Gasket Amazon eBay
150-97390REAR MAIN OIL SEAL RETAINER GASKET1Gasket Amazon eBay
153-97390REAR MAIN OIL SEAL1Seal Amazon eBay
154-97390REAR WATER JACKET COVER GASKET1Gasket Amazon eBay
158-A4531Oil Seal, Crankshaft, Rear1Seal Amazon eBay
160-97390OIL PAN GASKET1Gasket Amazon eBay
161-A4531O-ring, Engine Oil Filler1Seal Amazon eBay
164-A4531Gasket, Engine Oil Pan Drain Plug1Gasket Amazon eBay
172-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
173-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
174-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
175-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
176-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
177-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
178-A4531Gasket, Timing Belt Cover1Gasket Amazon eBay
179-A4531Strainer, Engine Oil Pan1Oil filter Amazon eBay $29.95
180-A4531Gasket, Oil Strainer1Gasket Amazon eBay
182-97390TIMING BELT1Belt Amazon eBay
199-A4531Belt, Valve Timing1Belt Amazon eBay $89.99
20439BELT, FAN (3600 RPM)1Belt Amazon eBay FridayParts $27.99
20621BELT, FAN (1800 RPM)1Belt Amazon eBay
211-97390VALVE SEAL8Seal Amazon eBay
222-97390OIL PUMP1Pump Amazon eBay
230-A4531Seal, Intake Valve Stem (Rubber)8Seal Amazon eBay
231-A4531Seal, Exhaust Valve Stem (Rubber)4Seal Amazon eBay
237-A4531O-ring, Engine Front Case (16.8)1Seal Amazon eBay
238-A4531Oil Seal, Crankshaft, Front1Seal Amazon eBay $43.40
244-A4531FILTER-OIL1Oil filter Amazon eBay
247-97390THERMOSTAT1Thermostat Amazon eBay
247-A4531Water Pump Assembly1Pump Amazon eBay $115.13
257-A4531GASKET-INTAKE MANIFOLD1Gasket Amazon eBay $29.26
258-A4531GASKET-EXHAUST MANIFOLD1Gasket Amazon eBay $37.34
261-97390WATER PUMP GASKET1Gasket Amazon eBay
265-97390WATER PUMP1Pump Amazon eBay
266-A4531O-ring, Distributor1Seal Amazon eBay
267-A4531Pick-up Kit, Distributor1Sensor Amazon eBay
275-A4531Spark Plug4Spark plug Amazon eBay $22.57
2903211" HOSE 9/32" I.D. BUNA N1Hose Amazon eBay
39379BELT, FAN1Belt Amazon eBay
4101-97390HEAD GASKET1Gasket Amazon eBay
4148-97390OIL PUMP DRIVE SHAFT COVER GASKET1Gasket Amazon eBay
48665GASKET, WATER OUTLET1Gasket Amazon eBay
50108Spring1Sensor Amazon eBay
5096712" HOSE - 5/8" I.D. (sold by foot)1Hose Amazon eBay
50968720MM HOSE, 3/4 SAE-20R31Hose Amazon eBay
53667TEMPERATURE SENSOR1Sensor Amazon eBay
57522LOW LEVEL SENSOR1Sensor Amazon eBay
59194HOSE 5/8 I.D. X 53"1Hose Amazon eBay
59401GASKET-CARBURETOR1Gasket Amazon eBay
59402FILTER ELEMENT1Air filter Amazon eBay $18.00
60108GASKET, OIL FILTER SUPPORT1Sensor Amazon eBay
61903FFUEL LINE, LPG - 35" LONG35"Hose Amazon eBay
69811CAP-OIL DRAIN HOSE1Hose Amazon $59.72 eBay
69860CHOSE ASM.-OIL DRAIN1Hose Amazon eBay
73912AIR FILTER ELEMENT1Air filter Amazon eBay $63.99
75130BELT, WATER PUMP1Belt Amazon eBay
75885THERMOSTAT1Thermostat Amazon eBay $25.14
79199BELT, WATER PUMP1Belt Amazon eBay $18.88
82130BMPU, SPEED SENSOR, RPM1Sensor Amazon Amazon eBay
97402INTAKE / EXHAUST GASKET2Gasket Amazon eBay
98690EXHAUST ADAPTER GASKET1Gasket Amazon eBay
98907THERMOSTAT GASKET1Gasket Amazon eBay
99021OIL FILTER1Oil filter Amazon eBay
99236Oil Press Switch1Sensor Amazon eBay $9.99 FridayParts $11.41
99478WATER TUBE GASKET1Gasket Amazon eBay
99512COIL COVER GASKET1Gasket Amazon eBay
A5275V-BELT (1800 RPM)1Belt Amazon eBay
A5554SEAL-QUAD RING, THERMOSTAT1Seal Amazon eBay $11.00
A5586V-BELT (3600 RPM)1Belt Amazon eBay $39.09
A6258HOSE, UPPER1Hose Amazon eBay
A6284HOSE, LOWER1Hose Amazon eBay
A6751SWITCH-WATER TEMPERATURE1Sensor Amazon eBay
A7006SEAL- O-RING1Seal Amazon eBay
A8584SWITCH-OIL PRESSURE1Sensor Amazon eBay
C3714HOSE ASSEMBLY NG/ LPG (1.5L)1Hose Amazon eBay
057329-TR-200B ControllerService part / kit Amazon eBay
0H7306Cover190Service part / kit Amazon eBay
0K8636-C36/45 kW (2.4 L)1Service part / kit Amazon eBay
105-A4531Valve, PCV1Service part / kit Amazon eBay
109-A4531Cap Assembly, Engine Oil Filler1Service part / kit Amazon eBay
239-97390BREATHER1Service part / kit Amazon eBay
245-97390FLAME TRAP1Service part / kit Amazon eBay
261-A4531Cap Assembly, Distributor1Service part / kit Amazon eBay
264-A4531Rotor, Distributor1Service part / kit Amazon eBay
268-97390DISTRIBUTOR CAP1Service part / kit Amazon eBay
268-A4531Ignitor Kit, Distributor1Service part / kit Amazon eBay
269-97390ROTOR1Service part / kit Amazon eBay
270-97390PULSE COIL1Service part / kit Amazon eBay
271-97390VACUUM UNIT1Service part / kit Amazon eBay
272-97390ELECTRONIC MODULE1Service part / kit Amazon eBay
72557IGNITION COIL1Service part / kit Amazon eBay
72587COIL, IGNITION1Service part / kit Amazon eBay
A2666GASEOUS FUEL SOLENOID1Service part / kit Amazon eBay
A7097FUEL SOLENOID LP LIQUID1Service part / kit Amazon eBay
CntrlNexus001Control PanelService part / kit Amazon eBay
Maint024MaintenanceService part / kit Amazon eBay
QT045QT0451Service 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
1.6990.65
25%6.0941.53
50%9.0852.4
75%12.3793.27
100%15.7094.15
Prime2.460.65
Prime25%6.661.76
Prime50%10.492.77
Prime75%14.353.79
Prime100%18.214.81
Standby6.371.68
Standby25%9.12.9
Standby50%12.33.3
Standby75%15.04.0
Standby100%17.84.7

Available documents

Spec sheet — 0171410SBY (Generac)Spec sheet — 0172980SBY (Generac)Spec sheet — 0172990SBY (Generac)Spec sheet — 0187670SBY (Generac)Spec sheet — 0194240SBY (Generac)Spec sheet — 0199380sby-c-qt025-30-45-60 (Generac)Reference — 0172950SBY (Generac)Reference — 0173110SBY (Generac)
A real unit
Generac QT025 generator

Photo of a real Generac QT025 — from a surplusrecord.com listing, 2026.

Real-unit nameplate
Generac QT025 generator nameplate / data tag

Nameplate from a real Generac QT025 — from a surplusrecord.com listing, 2026. How to read one →

Full service, cheapest listings

Priced items from this model's own parts manual.

Air filter 59402$18.00
Belt 199-A4531$89.99
Spark plug 275-A4531$22.57
3 priced items$130.56
Other sets with this engine
Generac QT020Generac QT030