Honda GXV120

Honda GXV120 engineThe Honda GXV120 is a 118 cc (7.2 cu-in) single-cylinder air-cooled four-stroke internal combustion small gasoline engine with vertical shaft manufactured by Honda Motor Company for general-purpose applications, such as lawn mowers, commercial lawn and garden equipment, forestry equipment, construction and industrial equipment, agricultural equipment.

The Honda GXV120 engine has an OHV (overhead valve) design; horizontal type carburetor with butterfly valve; centrifugal mechanical governor; heavy-duty recoil or electric starter and transistorized magneto ignition system.

The cylinder bore is 60.0 mm (2.4 in) and the piston stroke is 42.0 mm (1.7 in), compression ratio rating is 8.0:1 or 8.7:1. The engine produced 4.0 HP (2.9 kW) of horsepower at 3,600 rpm and 8.0 Nm (0.82 kg·m, 5.92 ft·lb) of torque at 2,700 rpm.

General information

Engine Specifications
Model GXV120
Type 4-stroke, OHV, single cylinder
Displacement 118 cm 3 (7.2 cu-in)
Max. horsepower 4.0 HP (2.9 kW) at 3,600 rpm
Max. torque (crank PTO) 8.0 Nm (0.82 kg·m, 5.92 ft·lb) at 2,700 rpm
Carburetor Horizontal type, butterfly valve
Cooling system Forced-air
Ignition system Transistorized magneto ignition
Lubricating system Forced splash
Starting system Recoil starter / Self starter
Stoping system Ignition primary circuit ground
Fuel used Unleaded gasoline (octane number 86 or higher)
Fuel tank capacity 1.0 L (0.26 US qt)
Fuel consumption 250 g/HPh
PTO shaft rotation Counterclockwise (from PTO shaft side)

Cylinder Block and Head

The Honda GXV120 motor has cast iron cylinder sleeve, ball bearing supported forged steel crankshaft. The piston has two compression rings and one oil ring. Precision camshaft design offers precise valve timing and optimal valve overlap for better fuel efficiency.

Cylinder block
Compression ratio: 8.7:1 for engine with S/N: 100001-1219523
8.0:1 for engine with S/N: from 1219524
Bore x Stroke 60 X 42 mm (2.4 x 1.7 in)
Sleeve internal diameter 60.000 mm (2.3622 in)
Piston skirt outer diameter 59.985 mm (2.3616 in)
Number of piston rings (compression / oil): 2 / 1
Ring side clearance Top 0.015-0.045 mm (0.0006-0.0018 in)
Second 0.015-0.045 mm (0.0006-0.0018 in)
Ring end gap Top/Second 0.20-0.40 mm (0.008-0.016 in)
Oil 0.15-0.35 mm (0.006-0.014 in)
Ring width Top/Second 1.5 mm (0.06 in)
Oil 2.5 mm (0.10 in)
Connecting rod small end ID 13.005 mm (0.5120 in)
Connecting rod big end ID 26.02 mm (1.024 in)
Piston pin outer diameter 13.0 mm (0.5118 in)
Crankshaft crank pin outer diameter 25.98 mm (1.023 in)
Cylinder Head
Warpage (limit) 0.10 mm (0.004 in)
Valve Arrangement: OHV
Valves: 2
Stem outer diameter (standard): INTAKE 5.480 mm (0.216 in)
EXHAUST 5.440 mm (0.214 in)
Valve spring free length: 34.0 mm (1.339 in)
Camshaft outer diameter: 13.984 mm (0.5506 in)
Cam height: INTAKE 27.70 mm (1.09 in)
EXHAUST 27.75 mm (1.093 in)

Tightening torque specs

Tightening torque specs
Connecting rod lower cap 12 Nm; 1.2 kg·m; 9 ft·lb
Cylinder head bolt 24 Nm; 2.4 kg·m; 17 ft·lb
Flywheel nut 75 Nm; 7.5 kg·m; 54 ft·lb
Pivot adjusting nut 10 Nm; 1.0 kg·m; 7 ft·lb
Pivot bolt 24 Nm; 2.4 kg·m; 17 ft·lb
Oil filter extension 10 Nm; 1.0 kg·m; 7 ft·lb
Oil drain bolt 18 Nm; 1.8 kg·m; 13 ft·lb
Oil pan 24 Nm; 2.4 kg·m; 17 ft·lb
Standard torque values
Bolt, nut (5 mm) 5.5 Nm; 0.55 kg·m; 4.0 ft·lb
Bolt, nut (6 mm) 10 Nm; 1.0 kg·m; 7 ft·lb
Bolt, nut (8 mm) 24 Nm; 2.4 kg·m; 17 ft·lb
Bolt, nut (10 mm) 37.5 Nm; 3.75 kg·m; 27 ft·lb
Bolt, nut (12 mm) 55 Nm; 5.5 kg·m; 40 ft·lb

Service Information

Maximum speed 3,100 ± 100 rpm
Idle speed 2,000 ± 150 rpm
Cylinder compression 3.0-7.0 kg/cm2 (44-100 psi) at 600 rpm
Valve clearance
Intake valve clearance 0.15±0.02 mm (0.006±0.001 in)
Exhaust valve clearance 0.20±0.02 mm (0.008±0.001 in)
Oil system
Oil type Honda 4-stroke or an equivalent (SE or SF)
Recommended oil SAE 10W-30
Oil capacity 0.6 L (0.63 US. qt, 0.53 Imp. qt.)
Main jet #65
Float height 12.2-15.2 mm (0.48-0.60 in)
Pilot screw opening 3 turns out
Ignition system
Ignition timing 25° B.T.D.C.
Spark plug NGK: BP5ES, BPR5ES
Spark plug gap 0.7-0.8 mm (0.028-0.031 in)
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.


  1. Buenos dias nesecito cotisacion de unos anillos y balbula de escape de motor hondagxv120 max.4ohp 3.0kw 118cc

  2. Hi, I am looking for a part# for vale stem seals for this GXV120-118 engine.
    Any help would be appreciated.

Leave a Reply

Your email address will not be published.