Honda G28

Honda G28 engineThe Honda G28 is a 67 cc (4.09 single-cylinder, air-cooled, four-stroke, internal combustion small gasoline engine manufactured by Honda Motor Company since 1969 for general-purpose applications.

The G28 has an overhead camshaft and an efficient combustion chamber designs together with a high-performance carburetor. Friction components such as the cylinder sleeve and piston are made of high strength materials. The crankshaft is mounted on ball bearings for reduced friction.

The Honda G28 engine compression ratio rating is 8.3:1, cylinder bore and piston stroke are 49.0 mm (1.93 in) and 35.5 mm (1.40 in), respectively.

The G28 produced 2.0 PS (1.49 KW; 2.0 HP) at 5,000 rpm of continuous rated horsepower and from 2.8 PS (2.08 KW; 2.8 HP) to 3.0 PS (2.23 KW; 3.0 HP) at 6,000 rpm of maximum horsepower.

General information

Engine Specifications
Type4-stroke, single cylinder
Displacement67 cm 3 (4.09 cu-in)
Max. horsepower 2.8 PS (2.08 KW; 2.8 HP) at 6,000 rpm
3.0 PS (2.23 KW; 3.0 HP) at 6,000 rpm
Max. torque
CarburetorHorizontal, butterfly valve
Cooling systemForced-air
Ignition systemHigh voltage ignition
Lubricating systemSplash type
Starting systemRecoil starter
Stoping systemGround switch
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel tank capacity2.6 liters (2.75 US.qts, 2.29 Imp. qts)
PTO shaft rotationCounterclockwise (from PTO shaft side)

Maintenance data

Oil system
Oil typeHonda 4-stroke or an equivalent
Recommended oilSAE 10W-30 or 10W-40
Oil capacity0.7 liters (0.74 US.qts, 0.62 Imp. qts)
Ignition system
Spark plugNGK: C-6HB
Spark plug gap0.6-0.7 mm (0.024-0.028 in)
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.

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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.


    • Check the oil level with the dipstick gauge on the oil filler cup:
      Upper limit-Lower lip of the oil filler opening.
      Lower limit-Ridge on the dipstick gauge.

  1. Hello, I have a Honda G28 motor/generator. I have had trouble getting spare parts for the motor. Possibly due to the age of the unit. Is there a modern day replacement Honda motor that I can use instead of the G28. Thanks.

    • Hi
      I’m having the same trouble
      Alot of the new motors turn anticlockwise on the pto for starters

      Did you receive any replys on replacement engine or even parts?

  2. I need a photo of the top of a g28 engine as I have 1 but the choke and accelerator wire have been removed and hard to find which way they go back on

  3. Hi I have a G28 and need a carburettor or replacement plastic bubble on the bottom as it has distorted with the heat from the exhaust. The carb is fine I think there must be a modification but not find the info needed.

    • Hi Nigel, mine has been missing the plastic bubble for years. when i bought it it had a bolt and washer holding the float bowl on instead and has run like that ok since. if you need a pic of the carb let me know

  4. I have a waterpump honda g28 it runs good but no starter.
    Do you have one? I can even sel the engine. I live in the Nederlands.

  5. Hi I’m after a g28 motor for my Honda tiller does any one have one or know where I can get one from …..I’m from Tasmania which is part of Australia

  6. Hey I have an old Honda g28 engine but I can’t understand how I would connect the accelerator to the carburettor

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