PORTABLE PROFESSIONAL POWER
GX120 Series
Honda's line of GX120 series engines are trusted by professionals across a multitude of industries. GX120 engines power a wide variety of equipment including plate compactors, reel mowers, walk-behind edgers, concrete saws, pot pullers, aerators, pumps, pavement stripers, paint sprayers and more. Equipped with large fuel tanks for extended runtimes, heavy-duty recoil starters for dependable start-ups and precision engineered components for reduced noise and vibration, a GX120 engine is sure to keep the equipment you depend on running for years to come.
Overhead Valve (OHV) Design
The GX120's valves are located above the combustion chamber allowing for enhanced fuel mixture intake, more complete exhaust and a higher compression ratio. The OHV layout of Honda's GX120 engines results in greater power output, reduced cylinder distortion and more efficient oil consumption for longer maintenance intervals.
Heavy Duty Recoil Starter
The GX120's large, easy-to-grip recoil starter handle coupled with with Honda's automatic mechanical decompression system makes for easy starting every time.
Precision Engineered Components
Honda's high-quality parts are less-prone to wear and corrosion for a longer engine life and provide minimal vibration and increased stability during operation.
Air-Cooled
Simple, lightweight engine design that is easy to maintain
4-Stroke
No oil/gas mixing required for cleaner emissions and better fuel efficiency
High Compression Ratio
Increased power output and thermal efficiency without an increase in engine size
GX120 Engine Series Specs
Learn more about the key specifications present on all gas-powered Honda GX120 engine models
Displacement: 118cc | 7.2 cu. in.
Net Power: 3.5 HP @ 3600 RPM
Net Torque: 5.4 ft lbs @ 2500 RPM
Starting System: Recoil
Carburetor Type: Butterfly
Bore x Stroke: 2.4" x 1.7" | 60mm x 42mm
Ignition System: Transistor Magneto
Oil Capacity: 0.59 US quart
Fuel Tank Capacity: 2.1 US quarts
Governor System: Mechanical
Engine Type: Air-Cooled | 4-Stroke | OHV | Single Cylinder
Warranty: 3 Year Commercial & Consumer
Compare GX120 Engine Models
Explore the key technical differences between the Honda GX120 engine models we offer
Engines within the same series may look the same, but certain specifications won't be obvious in a photo! These important specs ultimately determine whether or not an engine is compatible with your unique application and equipment.
Please note: the most accurate way to determine the correct replacement engine is by identifying and providing your current engine's model and spec numbers. Learn where to find your engine's identifying information in our Find Your Engine Model Number guide >
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| Engine | GX120 HX2 | GX120 QX2 | GX120 QXS2 | GX120 SG24 | GX120 SJD2 |
| Crankshaft Diameter |
3/4" | 3/4" | 3/4" | 18mm | 18mm |
| Crankshaft Length |
1.97" | 2-7/16" | 2-27/64" | 1.97" | 1.97" |
| Gear Reduction |
6:1 | --- | --- | --- | --- |
| Common Applications |
Aerators, Pot Pullers, Reel Mowers, Sprayers, Pumps | Compactor Plates, Pumps, Reel Mowers, Concrete Saws | Paint Sprayers, Laser Striping Machines | Plate Compactors, Reel Mowers | Reel Mowers |
| Oil Alert | Yes | Yes | Yes | Yes | No |
Shop GX120 Engines
