Briggs and Stratton 303447

Briggs and Stratton 303447The Briggs and Stratton 303447 Vanguard is a 495 cc, (30.2 cu·in) natural aspirated two-cylinders four-stroke air-cooled internal combustion gasoline engine with a horizontal shaft, for general-purpose applications.

Cylinder bore and piston stroke are 68.0 mm (2.68 in) and 66.0 mm (2.6 in), respectively. The compression ratio rating is 8.2:1. This engine produced 16.2 PS (11.9 kW; 16.0 HP) at 3,600 rpm of horsepower.

The B&S 303447 features:

  • OHV design
  • Magneto electronic ignition system
  • Float type, down-draft carburetor
  • Centrifugal governor
  • Full pressure lubrication system with spin-on oil filter
  • Forced air cooling system
  • Electric starter

General information

Engine Specifications
Engine model 303447 Vanguard
Engine type 4-stroke, OHV, V-twin
Displacement 495 cm3, (30.2 cu·in)
Max. horsepower 16.2 PS (11.9 kW; 16.0 HP) at 3,600 rpm
Max. torque
Cooling system Forced air
Air cleaner Low profile dual-clean
Lubricating system Full pressure lubrication with spin-on oil filter
Ignition system Magneto electronic
Fuel system Float type, down-draft carburetor
Fuel used Gasoline
Starting system Electric starter
Governor Centrifugal governor
Charging system Alternator 12V, 16A
Dimensions (L x W X H) 279 x 410 x 438 mm (11 x 16.1 x 17.2 in)
Dry weight 32.7 kg (72.1 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio: 8.2:1
Cylinder bore: 68.0 mm (2.68 in)
Piston stroke: 66.0 mm (2.6 in)
Cylinder internal diameter (standard): 68.000-68.030 mm (2.6772-2.6783 in)
Number of piston rings (compression / oil): 2/1
Connecting rod big end diameter (standard): 37.060-37.080 mm (1.4591-1.4598 in)
Connecting rod small end diameter (standard): 17.090-17.100 mm (0.6728-0.6732 in)
Piston pin diameter: 17.070-17.080 mm (0.672-0.6724 in)
Side clearance (Top): 0.045-0.076 mm (0.0018-0.003 in)
Side clearance (Second): 0.045-0.076 mm (0.0018-0.003 in)
Side clearance (Oil): 0.110-0.150 mm (0.0043-0.0059 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)
Crankshaft main journal diameter (magneto side): 29.980-30.000 mm (1.1803-1.1811 in)
Crankshaft main journal diameter (PTO side): 34.960-34.970 mm (1.3765-1.3770 in)
Crankpin journal diameter: 37.000-37.020 mm (1.4567-1.4575 in)
Crankshaft center distance: 33.0 mm (1.3 in)
Cylinder head
Valve arrangement: OHV, gear driven
Valves: 2 (4 valves in total)
Valve steam diameter (INTAKE): 5.950-5.960 mm (0.2343-0.2346 in)
Valve steam diameter (EXHAUST): 5.940-5.950 mm (0.2339-0.2343 in)
Camshaft lobe height (INTAKE): 30.330-30.530 mm (1.1941-1.202 in)
Camshaft lobe height (EXHAUST): 30.330-30.530 mm (1.1941-1.202 in)
Camshaft journal diameter (magneto side): 15.950-15.970 mm (0.628-0.6287 in)
Camshaft journal diameter (PTO side): 19.940-19.960 mm (0.785-0.7858 in)

Tightening torque

Tightening torque specs
Alternator (to cylinder) 2.0 Nm; 1.5 ft·lb
Air cleaner base (to carburetor) 7.0 Nm; 5.2 ft·lb
Air cleaner support bracket 7.0 Nm; 5.2 ft·lb
Alternator 2.0 Nm; 1.5 ft·lb
Armature 3.0 Nm; 2.2 ft·lb
Blower housings 7.0 Nm; 5.2 ft·lb
Back plate 7.0 Nm; 5.2 ft·lb
Breather 3.0 Nm; 2.2 ft·lb
Carburetor to manifold 7.0 Nm; 5.2 ft·lb
Connecting rod 13.0 Nm; 6.9 ft·lb
Crankcase cover 17.0 Nm; 12.6 ft·lb
Cylinder head 19.0 Nm; 14.1 ft·lb
Cylinder shield 7.0 Nm; 5.2 ft·lb
Exhaust manifold 17.0 Nm; 12.6 ft·lb
Flywheel nut 175.0 Nm; 129.6 ft·lb
Fan Retainer 17.0 Nm; 12.6 ft·lb
Governor lever nut 8.0 Nm; 5.9 ft·lb
Governor control bracket 16.0 Nm; 11.9 ft·lb
Intake manifold to cylinder head 16.0 Nm; 11.9 ft·lb
Oil pump 7.0 Nm; 5.2 ft·lb
Rewind starter (to blower housing) 7.0 Nm; 5.2 ft·lb
Rocker arm lock nut 7.0 Nm; 5.2 ft·lb
Rocker arm stud 11.0 Nm; 8.2 ft·lb
Starter motor 16.0 Nm; 11.9 ft·lb
Starter motor thru bolts 6.0 Nm; 4.4 ft·lb
Valve cover 3.0 Nm; 2.2 ft·lb

Service Data

Valve clearance
Intake valve clearance (COLD): 0.10-0.15 mm (0.004-0.006 in)
Exhaust valve clearance (COLD): 0.10-0.15 mm (0.004-0.006 in)
Oil system
Lubrication system: Full pressure by gear-driven oil pump
Oil type: SF, SG, SH, SJ or higher
Recommended oil: Summer: SAE 30W
Winter: SAE 5W-20, 5W-30
Oil capacity: 1.65 L (1.74 US. qt, 1.45 Imp. qt.)
Fuel system
Type: Float type, down-draft carburetor
Ignition system
Type: Electronic
Spark plug: Champion RC12YC
Spark plug gap: 0.7-0.8 mm (0.0276-0.0315 in)
Spark plug torque: 23 N·m (2.3 kg·m, 17 ft·lb)
Armature air gap 0.2-0.3 mm (0.008-0.012 in)

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