Honda GX22

Honda GX22 engineThe Honda GX22 is a 22 cc single-cylinder air-cooled four-stroke internal combustion ultra-small gasoline engine manufactured by Honda Motor Company since 1997. In 2002 the GX22 engine were replaced with the Honda GX25.

Honda developed the compact, lightweight, and 360°-inclinable 4-stroke GX22 engine, in the aim of producing a 4-stroke engine as easy to use as a 2-stroke. The GX22 engine is a suitable power source for handheld applications like brush-cutters and non-handheld applications like concrete screeds, tillers, and pumps.

This engine has an OHV design with valve rocker arms and camshaft driven by a maintenance-free, low-noise timing belt, makes the engine more compact and light.

It has a recoil starter, diaphragm type carburetor, transistorized magneto ignition. Bore is 33.0 mm (1.3 in) and stroke is 26.0 mm (1.0 in). The Honda GX22 ultra-small motor produced 1.014 PS (1.0 HP, 0.74 kW) at 7000 rpm and 1.09 Nm (0.11 kg·m, 0.80 ft·lb) at 6500 rpm.

General information

Engine Specifications
Model GX22
Type 4-stroke, OHV, single cylinder
Displacement 22 cm 3 (1.3 cu-in)
Max. horsepower 1.014 PS (1.0 HP, 0.74 kW) at 7000 rpm
Max. torque 1.09 Nm (0.11 kg·m, 0.80 ft·lb) at 6500 rpm
Carburetor Diaphragm type
Cooling system Forced-air
Ignition system Transistorized magneto ignition
Lubricating system Pumping spray
Starting system Recoil starter
Stoping system Ignition primary circuit ground
Fuel used Unleaded gasoline (octane number 86 or higher)
Fuel tank capacity 0.45 L (0.12 US gal, 0.10 lmp gal)
Fuel consumption 340 g/kWh (250 g/HPh, 0.55 lb/HPh)
PTO shaft rotation Counterclockwise (from PTO shaft side)

Dimensions and Weight

Length, mm (in) 210 (8.3)
Width, mm (in) 251 (9.9)
Height, mm (in) 249 (9.8)
Dry weight, kg (lb) 3.3 (7.3)

Cylinder Block and Head

Cylinder block
Compression ratio: 8.0:1
Bore x Stroke 33 X 26 mm (1.3 x 1.0 in)
Sleeve internal diameter 33.00 mm (1.299 in)
Piston skirt outer diameter 32.99 mm (1.298 in)
Ring end gap Top/second 0.10-0.25 mm (0.004-0.010 in)
Ring width Top/second 0.98 mm (0.039 in)
Oil 0.015-0.050 mm (0.006-0.0020 in)
Cylinder Head
Warpage (max) 0.2 mm (0.01 in)
Valve Arrangement: OHV
Valves: 2
Stem outer diameter (standard): INTAKE 3.985 mm (0.1569 in)
EXHAUST 3.950 mm (0.1555 in)
Valve guide outer diameter 4.000 mm (0.1575 in)
Cam height: INTAKE 22.79 mm (0.897 in)
EXHAUST 22.79 mm (0.897 in)
Camshaft outer diameter: 5.020 mm (0.1976 in)

Maintenance data

Idle speed 3100 ± 200 rpm
Cylinder compression 2.9-5.9 kg/cm2 (0.3-0.6 MPa, 41-84 psi) at 1200 rpm
Valve clearance
Intake valve 0.12 ± 0.02 (0.005 ± 0.001)
Exhaust valve 0.15 ± 0.02 (0.006 ± 0.001)
Main jet #36
Oil system
Oil type Honda 4-stroke or an equivalent (SG, SF)
Recommended oil SAE 10W-30
Oil capacity 0.1 L (0.1 US gal, 0.1 lmp qt)
Ignition system
Ignition timing 27 ° B.T.D.C (Fixed)
Spark plug NGK: C5HSB, CR5HSB
Spark plug gap 0.6-0.7 mm (0.024-0.028 in)
Primary ignition coil resistance 0.7-0.9 kΩ
Secondary ignition coil resistance 3.6-5.5 kΩ
Ignition coil air gap 0.35-0.5 mm (0.014-0.020 in)

Tightening torque specs

Tightening torque specs
Flywheel nut (M8) 15 Nm; 1.5 kg·m; 11 ft·lb
Crankcase bolt (M5 5×55 mm) 7 Nm; 0.75 kg·m; 5.1 ft·lb
Crankcase bolt (M5 5×18 mm) 5 Nm; 0.55 kg·m; 3.6 ft·lb
Camshaft cover bolt (M4) 3 Nm; 0.35 kg·m; 2.2 ft·lb
Recoil starter pulley (M8) 8 Nm; 0.8 kg·m; 5.8 ft·lb
Clutch bolt (M6) 10 Nm; 0.1 kg·m; 7 ft·lb
Cylinder head cover bolt (M5) 4 Nm; 0.4 kg·m; 2.9 ft·lb
Standard torque values
Bolt, nut (5 mm) 5.5 Nm; 0.55 kg·m; 4.0 ft·lb
Screw (3 mm) 1 Nm; 0.1 kg·m; 0.7 ft·lb
Screw (6 mm) 9 Nm; 0.9 kg·m; 6.5 ft·lb
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

ATTENTION! Dear visitors, this site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.


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