The Honda G300 is a 272 cc (16.6 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with a horizontal shaft, manufactured by Honda Motor Company for general-purpose applications.
A 76.0 mm (2.99 in) cylinder bore and 60.0 mm (2.36 in) piston stroke give the G300 engine a total of 272 cc of displacement. The compression ratio rating is 6.5:1.
The Honda G300 engine produced 7.1 PS (5.2 kW; 7.0 HP) at 3,600 rpm of maximum output power and 15.0 N·m (1.5 kg·m, 11.1 ft·lb) of peak torque.
The Honda G300 features:
- L-head design
- Transistorized magneto or contact point breaker (CDI) ignition system
- Horizontal type carburetor with butterfly valve
- Centrifugal govervor
- Splash lubrication system
- Forced air cooling system
- Recoil or electric starter
General information
Engine Specifications | |
Engine model | G300 |
Engine type | 4-stroke, L-head, single-cylinder |
Displacement | 272 cm3, (16.6 cu·in) |
Max. horsepower | 7.1 PS (5.2 kW; 7.0 HP) at 3,600 rpm |
Max. torque | Crankshaft PTO: 15.0 N·m (1.5 kg·m, 11.1 ft·lb) Camshaft PTO: 29.0 N·m (3.0 kg·m, 12.7 ft·lb) 1/2 reduction: 29.0 N·m (3.0 kg·m, 12.7 ft·lb) 1/6 reduction: 88.0 N·m (9.0 kg·m, 65.1 ft·lb) |
Cooling system | Forced air |
Air cleaner | Semi-dry type Dry type Oil bath type |
Lubricating system | Splash type |
Ignition system | Transistorized magneto or contact point breaker (CDI) |
Fuel system | Horizontal type carburetor with butterfly valve |
Fuel consumption | 285 g/HPh |
Fuel tank capacity | 6.0 L (1.59 US. gal. 1.32 Imp. gal.) |
Fuel used | Unleaded gasoline (octane number 86 or higher) |
Starting system | Recoil or electric starter |
Stoping system | Ignition primary circuit ground |
Governor | Centrifugal govervor |
PTO shaft rotation | Counterclockwise (from PTO shaft side) |
Dimensions (L x W X H) | – |
Dry weight | – |
Cylinder Block and Head
Cylinder block | |
Compression ratio: | 6.5:1 |
Cylinder bore: | 76.0 mm (2.99 in) |
Piston stroke: | 60.0 mm (2.36 in) |
Cylinder internal diameter (standard): | 76.000-76.017 mm (2.9921-2.9928 in) |
Piston skirt outer diameter (standard): | 75.970-76.000 mm (2.9909-2.9921 in) |
Number of piston rings (compression / oil): | 2/1 |
Connecting rod small end diameter (standard): | 16.005-16.020 mm (0.6301-0.6307 in) |
Side clearance (Top): | 0.020-0.060 mm (0.0008-0.0024 in) |
Side clearance (Second): | 0.010-0.050 mm (0.0004-0.002 in) |
Side clearance (Oil): | 0.010-0.050 mm (0.0004-0.002 in) |
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): | 0.200-0.400 mm (0.0079-0.0157 in) |
Ring width (Top): | 1.970-1.990 mm (0.0776-0.0783 in) |
Ring width (Second): | 1.970-1.990 mm (0.0776-0.0783 in) |
Ring width (Oil): | 3.970-3.990 mm (0.1563-0.1571 in) |
Crankpin journal diameter: | 29.943-29.959 mm (1.1789-1.1795 in) |
Cylinder head | |
Valve arrangement: | L-head |
Valves: | 2 |
Valve steam diameter (INTAKE): | 6.955-6.970 mm (0.2738-0.2744 in) |
Valve steam diameter (EXHAUST): | 6.910-6.925 mm (0.272-0.2726 in) |
Valve spring free length (INTAKE): | 42.7 mm (1.6811 in) |
Valve spring free length (EXHAUST): | 42.7 mm (1.6811 in) |
Camshaft lobe height (INTAKE): | 38.460-38.720 mm (1.5142-1.5244 in) |
Camshaft lobe height (EXHAUST): | 38.460-38.720 mm (1.5142-1.5244 in) |
Tightening torque
Tightening torque specs | |
Fuel valve (12 mm) | 12-15 Nm; 1.2-1.5 kg·m; 8.7-10.8 ft·lb |
Flywheel (16 mm) | 110-120 Nm; 11.0-12.0 kg·m; 80-87 ft·lb |
Cylinder head | 24-26 Nm; 2.4-2.6 kg·m; 17-19 ft·lb |
Tappet cover (6 mm) | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
Crankcase cover (8 mm) | 20-24 Nm; 2.0-2.4 kg·m; 15-17 ft·lb |
Connecting rod | 12.6-15.4 Nm; 1.26-1.54 kg·m; 9.1-11 ft·lb |
Fuel tank (8 mm) | 20-28 Nm; 2.0-2.8 kg·m; 15-20 ft·lb |
Oil drain plug | 15-25 Nm; 1.5-2.5 kg·m; 11-18 ft·lb |
Others | |
5 mm bolts, nuts | 4-7 Nm; 0.4-0.7 kg·m; 2.9-5.1 ft·lb |
6 mm bolts, nuts | 8-12 Nm; 0.8-1.2 kg·m; 5.8-8.7 ft·lb |
8 mm bolts, nuts | 20-28 Nm; 2.0-2.8 kg·m; 14.5-20.3 ft·lb |
10 mm bolts, nuts | 35-40 Nm; 3.5-4.0 kg·m; 25-29 ft·lb |
Service Data
Idle speed: | 1,400±150 rpm |
Cylinder compression: | 5.3 kg/cm2 (75 psi) |
Valve clearance | |
Intake valve clearance: | 0.08-0.16 mm (0.0031-0.0063 in) |
Exhaust valve clearance: | 0.11-0.19 mm (0.0043-0.0075 in) |
Oil system | |
Lubrication system: | Splash |
Oil type: | Honda 4-stroke “SE” |
Recommended oil: | SAE 10W-40 |
Oil capacity: | 1.2 L (1.27 US. qt, 1.06 Imp. qt.) |
Reduction device oil capacity: | 1/2 reduction: 0.3 L (0.32 US. qt, 0.26 Imp. qt.) 1/6 reduction: 0.15 L (0.16 US. qt, 0.13 Imp. qt.) |
Fuel system | |
Type: | Horizontal type carburetor with butterfly valve |
Main jet: | #88 |
Float height: | 8.2 mm (0.3228 in) |
Fuel tank capacity | 6.0 L (1.59 US. gal. 1.32 Imp. gal.) |
Ignition system | |
Type: | Transistorized magneto or contact point breaker (CDI) |
Ignition timing: | Magneto ignition: 20° B.T.D.C. The CDI type does not require adjustment |
Spark plug: | Magneto ignition: NGK B4H, BR4HS CDI ignition: NGK BP4HS-10, BPR4HS-10 |
Spark plug gap: | Magneto ignition: 0.6-0.7 mm (0.0236-0.0276 in) CDI ignition: 0.9-0.10 mm (0.0350-0.0390 in) |
Applications
Manufacturer or Brand | Models |
Generators | |
Honda | E2500, EB2800 EB3000 |
We try to use official documentation and verify the published data, but errors may occur. In addition, specifications of machinery and equipment may vary depending on markets and modifications. We do not recommend the use of this data for spare parts or repairs. Use official service manuals or parts catalogs for your product.
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