DEPENDABLE POWER. PROVEN PERFORMANCE.
GX390 Series
Built for demanding jobs and dependable performance, Honda’s line of GX390 engines deliver the power, durability, and efficiency professionals need to keep equipment running smoothly. Featuring a rugged overhead valve (OHV) design, fuel-efficient operation, easy starting, and reduced noise and vibration, the GX390 is engineered for reliable performance in tough working conditions. Its durable cast-iron cylinder sleeve, Oil Alert protection, and convenient maintenance features help support long service life and minimize downtime. With a versatile design suited to a wide range of equipment, Honda GX390 engines are an excellent choice for pressure washers, pumps, air compressors, concrete saws, hydraulic trailers, chippers and shredders, stump grinders, grain augers and much more. When your business depends on consistent power and proven reliability, the Honda GX390 is built to help you get the job done.
Overhead Valve (OHV) Design
The GX390'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 GX390 engines results in greater power output, reduced cylinder distortion and more efficient oil consumption for longer maintenance intervals.
Capacitor Discharge Ignition
The GX390's CDI system stores electrical energy in an internal capacitor and releases it in a fast, high-voltage burst to the spark plug providing reliable cold starts, high RPM performance and quick voltage rise 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
GX390 Engine Series Specs
Learn more about the key specifications present on all gas-powered Honda GX390 engine models
Displacement: 389cc | 23.7 cu. in.
Net Horsepower: 11.1 HP @ 3600 RPM
Max Torque: 18.4 ft lbs @ 2500 RPM
Bore x Stroke: 3.5" x 2.5" | 88mm x 64mm
Ignition System: CDI Type Magneto
Oil Capacity: 37 US oz
Lubrication System: Forced Splash
Compression Ratio: 8.2 : 1
Engine Type: Air-Cooled | 4-Stroke | OHV | Single Cylinder
Warranty: 3 Year Commercial & Consumer
Compare GX390 Engine Models
Explore the key technical differences between the Honda GX390 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 >
 |
 |
 |
 |
|
| Engine | GX390 HA2 | GX390 PA2 | GX390 PAE2 | GX390 QA2 |
| Crankshaft Diameter |
1" | 1" | 1" | 1" |
| Crankshaft Length |
3.37" | 3-1/2" Threaded | 3-1/2" Threaded | 3-31/64" |
| Gear Reduction |
6:1 | --- | --- | --- |
| Air Filter |
Dual Element | Dual Element | Dual Element | Dual Element |
| Starting System | Recoil | Recoil | Recoil & Electric | Recoil |
| Coil | --- | --- | 3 Amp Charging | --- |
 |
 |
 |
 |
|
| Engine | GX390 QAE2 | GX390 QC9 | GX390 QNE2 | GX390 QNR2 |
| Crankshaft Diameter |
1" | 1" | 1" | 1" |
| Crankshaft Length |
3-31/64" | 3-31/64" | 3-31/64" | 3-31/64" |
| Gear Reduction |
--- | --- | --- | --- |
| Air Filter |
Dual Element | Cyclone | Dual Element | Dual Element |
| Starting System | Recoil & Electric | Recoil | Recoil & Electric | Recoil & Electric |
| Coil | 3 Amp Charging | --- | 1 Amp Charging | 18 Amp Charging |
Shop GX390 Engines
