Honda GX390 Engine With Electric Start
The Honda GX390 is a 389cc, single-cylinder, 4-stroke OHV gas engine that produces 11.7 net horsepower and 19.5 lb-ft of torque. Before Honda switched to net power ratings, it was sold as the Honda 13 HP engine. This model adds a 12V electric starter, so it fires up at the turn of a key, plus Oil Alert protection and a standard 1" horizontal keyed crankshaft. That makes it a direct-fit repower for pressure washers, log splitters, generators, water pumps and other heavy-duty equipment.
When an engine fails, the machine around it is often still in good shape. Replacing the whole pressure washer or log splitter wastes money, while a cheap clone engine rarely lasts. The Honda GX390 engine gives you a better option. It's the commercial-grade engine many manufacturers build their equipment around, so you get proven Honda reliability for far less than new equipment.
Why the Honda GX390 Engine Is the Industry Standard
Strong, steady power. The GX390 delivers 11.7 HP (8.7 kW) at 3,600 rpm and 19.5 lb-ft of peak torque at 2,500 rpm. As a result, it drives pumps, compressors and hydraulic systems under heavy load without bogging down.
Commercial-grade construction. A cast-iron cylinder sleeve, forged steel crankshaft and ball-bearing-supported crankshaft stand up to daily professional use. A heavy-duty balancer shaft also keeps vibration low, which reduces wear on both the engine and your equipment.
Efficient, quieter operation. The OHV design, precision camshaft and digital CDI ignition with variable timing improve combustion efficiency. Meanwhile, a multi-chamber exhaust system keeps noise down on job sites and around the home.
Easy maintenance. Dual oil drains and fill points, an easy-to-reach spark plug and a dual-element air cleaner make routine service quick, even when the engine is mounted in tight equipment frames.
Honda GX390 Electric Start and Oil Alert
Turn-key electric start. The 12V electric starter starts the engine without pulling a cord, which helps when you start and stop equipment all day. Plus, the recoil starter stays in place as a backup, so you're never stranded if the battery runs low. An automatic decompression system also makes recoil starts noticeably easier.
Oil Alert engine protection. A crankcase sensor automatically shuts the engine down when the oil level drops too low. That single feature prevents the most common cause of small-engine failure: running without enough oil.
What the GX390 Engine Powers
The Honda GX390 engine is a popular repower and OEM engine for:
- Pressure washers and surface cleaners
- Log splitters and hydraulic power units
- Portable generators and welder generators
- Water pumps and trash pumps
- Air compressors
- Wood chippers and shredders
- Go-karts, mini bikes and small utility vehicles
- Tillers, concrete equipment and other construction tools
Will the Honda GX390 Fit My Equipment?
This engine uses the standard Honda horizontal-shaft layout with a 1" diameter keyed crankshaft, 3-31/64" long. Its universal mounting pattern matches previous GX390 versions, so equipment built for an earlier GX390 usually accepts it with no modifications. Before you order, check three things on your current engine:
- Shaft: 1" diameter, keyed, horizontal.
- Mounting: the bolt pattern on the engine base.
- Rotation: counterclockwise, viewed from the PTO (shaft) side.
Not sure about fitment? Send our team your current engine's model and type code, stamped on the engine shroud, and we'll confirm the match before you buy.
Honda GX390 Specifications
| Specification | Honda GX390 |
|---|---|
| Engine type | Air-cooled, 4-stroke, OHV, single cylinder, 25° inclined |
| Displacement | 389cc (23.7 cu in) |
| Bore × stroke | 88 × 64 mm |
| Compression ratio | 8.2:1 |
| Net power | 11.7 HP (8.7 kW) at 3,600 rpm (formerly rated 13 HP) |
| Net torque | 19.5 lb-ft (26.4 Nm) at 2,500 rpm |
| Crankshaft | Horizontal, 1" × 3-31/64", keyed and tapped |
| PTO rotation | Counterclockwise from the PTO side |
| Starting system | 12V electric start with recoil backup |
| Ignition | Digital CDI with variable timing |
| Oil Alert | Yes, automatic low-oil shutdown |
| Fuel | Unleaded gasoline, 86 octane or higher |
| Fuel tank capacity | 1.6 gal (6.1 L) |
| Fuel consumption | About 0.92 gal/h (3.5 L/h) at rated power |
| Oil capacity | 1.16 US qt (1.1 L) |
| Air cleaner | Dual element |
| Dry weight | About 69 lb (31.5 kg), recoil version; electric start adds starter weight |
| Warranty | Honda 3-year limited (consumer and commercial) |
Getting the Most From Your GX390
Fill the crankcase with SAE 10W-30 oil before the first start, because the engine ships dry. Change the oil after the first 20 hours of use to clear break-in particles, then follow Honda's regular service schedule. Check the oil level before every use, and keep the air cleaner clean, especially on dusty job sites. Simple habits like these are why GX390 engines routinely run for thousands of hours.
Buy Your Honda GX390 From Liniotech
Looking for a Honda GX390 for sale with fast shipping? Liniotech stocks the genuine Honda GX390 electric start engine and usually ships within 24 hours from Cypress, Texas. Our team can help you confirm fitment before you order, so your repower goes right the first time. Browse more Honda generators and portable power from Liniotech. Need fuel-free backup power for home instead? See our 1200W portable power station. For fitment questions, contact our team.
Get Your Honda GX390 Engine From Liniotech Today
Give your equipment the engine professionals trust. The Honda GX390 delivers commercial-grade power, turn-key electric start and Oil Alert protection in one proven 389cc package. Order your Honda GX390 engine from Liniotech today, or call 800-978-0161 or email sales@liniotech.com, and the Liniotech team will confirm fitment and get your engine on its way.
Frequently Asked Questions
Is the Honda GX390 a 13 HP engine?
Yes. Honda originally marketed the GX390 as a 13 HP engine using gross horsepower. Today, Honda rates it at 11.7 net HP under the SAE J1349 standard, which measures power with the muffler and air cleaner fitted. The engine itself is the same 389cc design.
Does the Honda GX390 come with electric start?
This model does. It includes a 12V electric starter for key starting, with the recoil pull-start kept as a backup. Electric start models need a 12V battery to operate the starter.
Does the GX390 electric start engine include a battery?
Most electric start GX390 engines ship without a starter battery or battery cables. Check the package contents before installation, and use a 12V battery sized for small-engine starting.
What does Oil Alert do on the Honda GX390?
Oil Alert uses a crankcase sensor to shut the engine down automatically when the oil level gets too low. This protects the engine from serious damage caused by running without enough oil.
What equipment uses a Honda GX390 engine?
The GX390 powers pressure washers, log splitters, generators, water pumps, air compressors, wood chippers, go-karts and construction equipment. Its standard 1" horizontal shaft makes it a popular repower engine.
Will a GX390 replace my old 13 HP Honda engine?
In most cases, yes. The current GX390 keeps the same universal mounting pattern and 1" crankshaft as earlier GX390 versions. Confirm the shaft length, keyway and rotation match your equipment before ordering.
How long does a tank of fuel last on the GX390?
The 1.6-gallon tank lasts about 1.7 hours at full rated power. At lighter, partial loads, which are typical for many tools, runtime is noticeably longer.
What oil does the Honda GX390 use?
Honda recommends SAE 10W-30 for general use, with a crankcase capacity of 1.16 US quarts (1.1 L). The engine ships without oil, so fill it before the first start.
What warranty does the Honda GX390 have?
The GX390 carries Honda's 3-year limited warranty for both consumer and commercial use, serviced through authorized Honda Engines dealers.
