Briggs and Stratton 28S777

Briggs and Stratton 28R707The Briggs and Stratton 28S777 Intek 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 B&S 28S777 engine produced 13.6 PS (10.0 kW; 13.5 HP) at 3,300 rpm of maximum horsepower.

The B&S 28S777 Intek features:

  • Cast iron sleeve
  • OHV (overhead valve) design
  • Plain bearing
  • Electronic ignition system
  • Float type carburetor
  • Centrifugal governor
  • Full pressure lubrication system
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine model 28S777 Intek
Engine type 4-stroke, OHV, single-cylinder
Displacement 465 cm3, (28.38 cu·in)
Max. horsepower 13.6 PS (10.0 kW; 13.5 HP) at 3,300 rpm
Max. torque
Cooling system Forced air
Air cleaner Paper filter with a foam pre-cleaner
Lubricating system Full pressure lubrication system
Ignition system Electronic
Fuel system Float type carburetor
Fuel consumption
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 (1.2476-1.2488 in)
Crankshaft center distance: 38.85 mm (1.53 in)
Cylinder head
Valve arrangement: OHV (overhead 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: Pulse 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)

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