The Honda GX390 is one of the most trusted commercial small engines in the pressure washing and industrial equipment industry. Delivering 11.7 HP from Honda’s proven 389cc GX Series platform, this horizontal shaft OHV engine combines dependable power, fuel efficiency, and long-term durability for demanding commercial applications.
Built with Honda’s commercial-grade engineering, the GX390 features a reliable recoil starting system, Oil Alert protection, and a quiet multi-chamber muffler system with integrated spark arrestor and deflector. The forged internal components, cast iron cylinder sleeve, and precision-engineered camshaft design help provide smooth operation and long engine life even under continuous heavy-duty use.
The GX390 is widely used throughout the pressure washing industry due to its reliability, strong torque output, and compatibility with direct-drive and belt-drive pump systems. Beyond pressure washing, the GX390 platform powers industrial sprayers, air compressors, trenchers, generators, and countless commercial equipment applications across multiple industries.
Honda’s Digital CDI ignition system with variable timing improves throttle response, fuel efficiency, and starting performance while helping reduce vibration and operating noise.
For contractors and equipment builders looking for a proven commercial engine platform with legendary reliability, the Honda GX390 remains one of the most trusted engines in the industry.
Not for sale in California.
Built for Commercial & Industrial Applications
- Pressure washers
- Belt-drive pressure washer systems
- Air compressors
- Industrial sprayers
- Lawn and agricultural equipment
- Sprayer pumps
- Trenchers and vibratory plows
- Generators
- Salt and sand spreaders
- Custom skid and trailer builds
What makes the Honda GX390 popular for pressure washers?
The GX390 is known throughout the pressure washing industry for its strong torque output, commercial reliability, smooth operation, and long service life. Its 389cc platform pairs well with many direct-drive and belt-drive pressure washer pump configurations.
Does the Honda GX390 include electric start?
No. This GX390 configuration utilizes a recoil pull-start system.
What size shaft does the Honda GX390 use?
This engine features a 1" diameter horizontal shaft with a 3-31/64" shaft length and 1/4" keyway.
What oil does the Honda GX390 use?
Honda recommends SAE 10W-30 engine oil for general operation across most temperature ranges
Commercial GX Series Platform:
Built for demanding industrial and commercial applications requiring dependable long-term performance.
11.7 HP OHV Engine Design:
Delivers strong torque and efficient power transfer for pressure washers and industrial equipment.
Recoil Pull Start System:
Simple and dependable manual starting system for commercial operation.
Digital CDI Ignition System:
Variable ignition timing improves throttle response, fuel efficiency, and starting performance.
389cc Commercial Engine:
Trusted throughout the pressure washing industry for durability and reliability.
Dual-Element Air Cleaner:
Helps extend filter life and improve protection in dusty work environments.
Oil Alert Protection System:
Automatically helps protect the engine from low-oil operating conditions.
Cast Iron Cylinder Sleeve:
Provides long-term durability under heavy commercial use.
Quiet Multi-Chamber Muffler:
Includes spark arrestor and deflector while helping reduce engine noise.
Precision Engineered Components:
Designed to reduce vibration and improve long-term operating smoothness.
| Specification | Details |
| Brand | Honda |
| Model | GX390UT2QA2 |
| Engine Series | GX Series |
| Engine Type | OHV Single Cylinder |
| Displacement | 389cc |
| Net Power Output | 11.7 HP |
| Start Type | Recoil Start |
| Ignition System | Digital CDI w/ Variable Timing |
| Shaft diameter | 1" |
| Shaft Length | 3-31/64" |
| Shaft Keyway | 1/4" |
| Shaft Orientation | Horizontal |
| Shaft Rotation | Counter-Clockwise |
| Fuel Type | Unleaded 86 Octane or Higher |
| Fuel Tank Capacity | 6.4 qt |
| Compression Ratio | 8.2:1 |
| Oil Capacity | 1.16 qt |
| Lubrication System | Splash |
| Air Cleaner Type | Dual Element |
| Cylinder Sleeve | Cast Iron |
| Charging System | 3 Amp w/ Rectifier |
| Muffler | Silent Muffler w/ Spark Arrestor & Deflector |
| Weight | 86 lbs |
| Warranty | 3-Year Limited Warranty |
What’s Included
- Honda GX390 QA2 Engine
- Recoil starter system
- Silent muffler with spark arrestor and deflector
The Honda GX390 QAE2 engine is backed by Honda’s 3-Year Limited Warranty for commercial and consumer applications.
As an authorized Honda dealer, Spraywell can assist customers with warranty support, product questions, and warranty service coordination.
For complete warranty terms, exclusions, and coverage details, please refer to Honda’s official warranty documentation or contact Spraywell directly at 561-964-3228.
