Briggs and Stratton 28M707

Briggs and Stratton 28M707The Briggs and Stratton 28M707 is a 465 cc, (28.4 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with a vertical shaft, manufactured by Briggs & Stratton for general-purpose applications.

Cylinder bore and piston stroke are 87.3 mm (3.44 in) and 77.7 mm (3.06 in), respectively. The 28M707 engine produced 13.1 PS (9.6 kW; 13.0 HP) at 3,300 rpm of maximum horsepower.

The B&S 28M707 features:

  • Cast iron sleeve
  • L-head (side valve) design
  • Electronic ignition system
  • Float type carburetor
  • Pulse type fuel pump
  • Centrifugal governor
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine model 28M707
Engine type 4-stroke, L-head (side valve), single-cylinder
Displacement 465 cm3, (28.38 cu·in)
Max. horsepower 13.1 PS (9.6 kW; 13.0 HP) at 3,300 rpm
Max. torque
Cooling system Forced air
Air cleaner Paper filter with a foam pre-cleaner
Lubricating system
Ignition system Electronic
Fuel system Float type carburetor
Fuel used Gasoline
Starting system Electric starter
Governor Centrifugal governor
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Compression ratio:
Cylinder bore: 87.3 mm (3.44 in)
Piston stroke: 77.7 mm (3.06 in)
Cylinder internal diameter (standard): 87.300-87.400 mm (3.437-3.4409 in)
Number of piston rings (compression / oil): 2/1
Connecting rod big end diameter (standard): 31.760-31.810 mm (1.2504-1.2524 in)
Connecting rod small end diameter (standard): 20.330-20.370 mm (0.8004-0.802 in)
Piston pin diameter: 20.290-20.310 mm (0.7988-0.7996 in)
Side clearance (Top): 0.03-0.07 mm (0.0012-0.0028 in)
Side clearance (Second): 0.03-0.07 mm (0.0012-0.0028 in)
Side clearance (Oil): 0.03-0.07 mm (0.0012-0.0028 in)
Ring end gap (Top): 0.15-0.35 mm (0.0059-0.0138 in)
Ring end gap (Second): 0.15-0.35 mm (0.0059-0.0138 in)
Ring end gap (Oil): 0.35-0.70 mm (0.0138-0.0276 in)
Crankshaft main journal diameter: 34.950 mm (1.376 in)
Crankpin journal diameter: 31.690-31.720 mm (1.2478-1.2489 in)
Crankshaft center distance: 38.85 mm (1.53 in)
Cylinder head
Valve arrangement: L-head (side valve), gear driven
Valves: 2
Valve steam diameter (INTAKE): 5.960-5.980 mm (0.2346-0.2354 in)
Valve steam diameter (EXHAUST): 5.960-5.980 mm (0.2346-0.2354 in)
Camshaft lobe height (INTAKE): 21.02 mm (0.8276 in)
Camshaft lobe height (EXHAUST): 21.02 mm (0.8276 in)

Tightening torque

Tightening torque specs
Air cleaner base 6.0 Nm; 4.4 ft·lb
Alternator 2.0 Nm; 1.5 ft·lb
Armature 3.0 Nm; 2.2 ft·lb
Blower housings 10.0 Nm; 7.4 ft·lb
Blower housing brackets 10.0 Nm; 7.4 ft·lb
Breather 4.0 Nm; 2.9 ft·lb
Carburetor to intake manifold 7.0 Nm; 5.2 ft·lb
Connecting rod 21.0 Nm; 15.6 ft·lb
Control bracket 5.0 Nm; 3.7 ft·lb
Crankcase cover 25.0 Nm; 18.5 ft·lb
Cylinder head 25.0 Nm; 18.5 ft·lb
Cylinder shield 5.0 Nm; 3.7 ft·lb
Exhaust manifold / adapter 19.0 Nm; 14.0 ft·lb
Flywheel nut 135.0 Nm; 100.0 ft·lb
Flywheel fan 16.0 Nm; 11.9 ft·lb
Fuel pump 5.0 Nm; 3.7 ft·lb
Governor lever nut 5.0 Nm; 3.7 ft·lb
Intake manifold to cylinder head 10.0 Nm; 7.4 ft·lb
Muffler 19.0 Nm; 14.1 ft·lb
Oil drain plug 14.0 Nm; 10.4 ft·lb
Oil pump cover 10.0 Nm; 7.4 ft·lb
Starter motor 16.0 Nm; 11.9 ft·lb

Service Data

Valve clearance
Intake valve clearance: 0.08-0.13 mm (0.0031-0.0051 in)
Exhaust valve clearance: 0.13-0.18 mm (0.0051-0.0071 in)
Oil type: SF, SG, SH, SJ or higher
Recommended oil: Summer: SAE 30, 10W-30
Winter: SAE 5W-30
Oil capacity: 1.40 L (1.48 US. qt, 1.23 Imp. qt.)
Fuel system
Type: Float type carburetor
Fuel pump: Pusle type
Ignition system
Type: Electronic
Spark plug: Champion RJ19LM
Spark plug gap: 0.7-0.8 mm (0.0276-0.0315 in)
Spark plug torque: 20 N·m (2 kg·m, 14.7 ft·lb)
Armature air gap 0.25-0.36 mm (0.0098-0.0142 in)
ATTENTION! Dear visitors, this is an informational database of technical specifications, we are not a parts supplier or a marketplace.

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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