Horizontal Shaft Engines


With the GX390, you’re looking at one of the best engines in the business. More power. Quieter performance. Lower fuel consumption. Lower emissions. Better features. Exceptional performance. Honda’s GX series lives up to the legend, and then some. Used in all kinds of commercial, agricultural and forest equipment. Its also used for small vehicles, water pumps and commercial lawn and garden equipment.


A digital CDI ignition system with variable timing and an increased compression ratio combines with the GX390's Precision Camshaft design to offer precise valve timing and optimal valve overlap for better fuel efficiency.

It draws on decades of Honda engineering with its OHV design, delivering increased efficiency and optimal power transfer where and when you need it.

The use of lightweight, noise-reducing materials and a forged steel crankshaft & rigid crankcase results in an exceptionally quiet engine – an improved piston design reduces mechanical noise, with an overall reduction of engine noise by up to 5dB.


The GX390 offers precision-engineered components resulting in lower vibration, and a Ball Bearing-supported Crankshaft for greater stability. It also offers an improved piston design and a heavy duty balancer shaft to deliver smooth performance.

Helical cut gears, a large capacity, multi-chamber exhaust system and sophisticated air intake system also makes for an exceptionally quiet engine.

And with oil alert, a simple throttle control, large Fuel Tank and automotive type fuel cap, dual oil drains and fills, an easily accessible spark plug make it easy to use and maintain.

Type4-stroke, overhead valve, single-cylinder, horizontal shaft
Bore & Stroke88 x 64mm
Displacement389 cc
Compression Ratio8.0:1
Net Power

8.2kW (11.0HP) at 3,600rpm

Max Net Torque25.1Nm at 2,500rpm
Ignition SystemTransistorised magneto ignition
Starting SystemRecoil (Electric Start Optional)
Cooling SystemForced-Air
PTO Shaft RotationCounter-clockwise (from P.T.O. side)
Fuel Consumption at Rated Power3.7 L/h at 3,600rpm
Recommended FuelUnleaded
Recommended Oil10W/30 API SG
Lubrication SystemSplash
Oil Capacity1.1 litres
Fuel Tank Capacity (Litres)6.1 litres
Dry Weight31 kg approx.
Length405 mm
Width450 mm
Height443 mm