Briggs and Stratton 386777

Briggs and Stratton 386777The Briggs and Stratton 386777 Vanguard is a 627 cc, (38.2 cu·in) natural aspirated two-cylinders four-stroke air-cooled internal combustion gasoline engine with a vertical shaft, for general-purpose applications.

Cylinder bore and piston stroke are 75.5 mm (2.97 in) and 70.0 mm (2.75 in), respectively. This engine produced 23.3 PS (17.1 KW; 23.0 HP) at 3,600 rpm of horsepower.

The B&S 386777 features:

  • OHV design
  • Electronic ignition system
  • Float type, side-draft carburetor
  • Centrifugal governor
  • Pressure lubrication, oil cooler
  • Forced air cooling system /li>
  • Electric starter

General information

Engine Specifications
Engine model 386777 Vanguard
Engine type 4-stroke, OHV, V-twin
Displacement 627 cm3, (38.2 cu·in)
Max. horsepower 23.3 PS (17.1 KW; 23.0 HP) at 3,600 rpm
Max. torque
Cooling system Forced air
Air cleaner Dual-Clean (paper element with a foam pre-cleaner)
Lubricating system Pressure lubrication, oil cooler
Ignition system 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) 407 x 428 x 319 mm (16.1 x 16.9 x 12.6 in)
Dry weight 44.8 kg (98.0 lbs)

Cylinder Block and Head

Cylinder block
Cylinder bore: 75.5 mm (2.97 in)
Piston stroke: 70.0 mm (2.75 in)
Cylinder internal diameter (standard): 75.500-75.520 mm (2.9724-2.9730 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): 18.040-18.050 mm (0.7100-0.7105 in)
Piston pin diameter: 18.000-18.010 mm (0.7085-0.7090 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): 34.990-35.010 mm (1.3776-1.3784 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: 35.0 mm (1.38 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): 31.090-31.300 mm (1.2240-1.2320 in)
Camshaft lobe height (EXHAUST): 30.330-30.530 mm (1.1940-1.2020 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: 0.10-0.15 mm (0.004-0.006 in)
Exhaust valve clearance: 0.10-0.15 mm (0.004-0.006 in)
Oil system
Lubrication system: Pressure lubrication, oil cooler
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, side-draft carburetor
Ignition system
Type: Electronic
Spark plug: Champion RC12YC
Champion XC92YC
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)
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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