Honda GX140

Honda GX140 engineThe Honda GX140 is a 144 cc (8.8 cu-in) single-cylinder, air-cooled, four-stroke, internal combustion small gasoline engine manufactured by Honda Motor Company since 1983 for general-purpose applications.

This engine has a single cylinder inclined by 25° overhead valve design for increased efficiency and optimal power transfer, sophisticated air intake system, large capacity, multi-chamber exhaust system, heavy-duty recoil starter.

A 64.0 mm (2.5 in) cylinder bore and 45.0 mm (1.77 in) piston stroke give the engine a total of 144 cc (8.8 cu-in) of displacement. The compression rato rating is 8.7:1. This engine produces 5.0 PS (3.6 KW; 4.8 HP) at 4,000 rpm and 9.8 Nm (1.0 kg·m; 7.23 lbf·ft) at 2,800 rpm of torque.

General information

Engine Specifications
Type4-stroke, OHV, single cylinder, inclined by 25°
Displacement144 cm 3 (8.78 cu-in)
Max. horsepower5.0 PS (3.6 KW; 4.8 HP) at 4,000 rpm
Max. torque (crank PTO)9.8 Nm (1.0 kg·m; 7.23 lbf·ft) at 2,800 rpm
CarburetorHorizontal type, butterfly valve
Cooling systemForced-air
Ignition systemTransistorized magneto ignition
Lubricating systemSplash
Starting systemRecoil starter
Stoping systemIgnition primary circuit ground
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel tank capacity3.6 l (0.95 US. Gal, 0.79 Imp. Gal.)
Fuel consumption230 g/HPh
PTO shaft rotationCounterclockwise (from PTO shaft side)

Dimensions and Weight

GX140 “S-Type”
Length, mm (in)315 (12.4)
Width, mm (in)355 (14.4)
Height, mm (in)335 (13.2)
Dry weight, kg (lb)14.0 (30.9)

Cylinder Block and Head

The Honda GX140 has cast iron cylinder sleeve, ball bearing supported crankshaft, improved piston design, heavy-duty balancer shaft.

Cylinder block
Compression ratio:8.7:1
Bore x Stroke64 mm X 45 mm (2.5 x 1.77 in)
Sleeve internal diameter64.000-64.015 mm (2.5196-2.5197 in)
Piston skirt outer diameter63.965-63.985 mm (2.5183-2.5190 mm)
Number of piston rings (compression / oil):2 / 1
Ring side clearance (Top)0.015-0.045 (0.0006-0.0018)
Ring side clearance (Second)0.015-0.045 (0.0006-0.0018)
Ring end gap (Top)0.200-0.400 mm (0.0079-0.0157 in)
Ring end gap (Second)0.200-0.400 mm (0.0079-0.0157 in)
Ring end gap (Oil)0.150-0.350 mm (0.006-0.0137 in)
Ring width (Top)1.5 mm (0.059 in)
Ring width (Second)1.5 mm (0.059 in)
Ring width (Oil)2.5 mm (0.98 in)
Piston pin outer diameter:17.994-18.000 mm (0.7084-0.7087in)
Crankshaft main journal diameter:30.000 mm (1.1811 in)
Cylinder Head
Warpage (limit)0.10 mm (0.004 in)
Valve Arrangement:OHV
Stem outer diameter (INTAKE):5.468-5.480 mm (0.2152-0.2157 in)
Stem outer diameter (EXHAUST):5.425-5.440 mm (0.2135-0.2141 in)
Cam height (INTAKE):27.70 mm (1.0905 in)
Cam height (EXHAUST):27.75 mm (1.0925 in)
Camshaft journal diameter:14.00 mm (0.5511 in)

Service Information

Maximum speed4,000 ± 150 rpm
Idle speed1,400 ± 150 rpm
Cylinder compression6.0-8.5 kg/cm2 (85-151 psi) at 600 rpm
TypeHorizontal type, butterfly valve
Main jet#68
Float height13.7±1.5 mm (0.54±0.06 in)
Pilot screw opening1 turns out
Oil system
Oil typeHonda 4-stroke or an equivalent (SE or SF)
Recommended oilSAE 10W-30
Oil capacity0.6 P (0.63 US. qt, 0.53 Imp. qt.)
Ignition system
Spark plugNGK: BPR6ES
Ignition timingB.T.D.C. 25° / 1,400 rpm
Spark plug gap0.7-0.8 mm (0.028-0.031 in)
Ignition coil air gap0.2-0.6 mm (0.01-0.02 in)

Engine applications

  • Pressure washers
  • Commercial lawn and garden equipment
  • Tillers / cultivators
  • Generators
  • Construction / industrial equipment
  • Agricultural equipment
  • Small vehicles
  • Water pumps
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.


  1. I have an older Honda GX140 5 hp with a “roughly” 3/4″ 14 tooth splined shaft. I need to couple this engine with a hydraulic pump. Any help?

  2. I have a plate compactor with this engine. The engine has no compression, and I’d like to replace it with a new equivalent. Any suggestions for a direct-swap.
    Or can anyone tell me the output shiaft diameter so I can find an equivalent motor.

  3. @Kenny Millar – The output shaft diameter should be 3/4 inch. I believe the GX140 engine is still available. If you are on a tight budget, you might consider the Lifan LF160F-AQ. It is a Chinese Honda clone (a “Chonda”) and is rated 4hp, not 5hp, but it should bolt right up. Lifan engines are probably the best Chonda engines available. I know both Home Depot and Amazon sell them.

Leave a Reply

Your email address will not be published.