Briggs and Stratton 351777

Briggs and Stratton 351777The Briggs and Stratton 351777 Vanguard is a 570 cc, (34.8 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 72.0 mm (2.83 in) and 70.0 mm (2.75 in), respectively. This engine produced 20.1 PS (14.8 KW; 20.0 HP) at 3,600 rpm of horsepower.

The B&S 351777 features:

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

General information

Engine Specifications
Engine model351777 Vanguard
Engine type4-stroke, OHV, V-twin
Displacement570 cm3, (34.8 cu·in)
Max. horsepower20.1 PS (14.8 KW; 20.0 HP) at 3,600 rpm
Max. torque
Cooling systemForced air
Air cleanerDual-Clean (paper element with a foam pre-cleaner)
Lubricating systemFull pressure lubrication with spin-on oil filter
Ignition systemMagneto electronic
Fuel systemFloat type, side-draft carburetor
Fuel usedGasoline
Starting systemElectric starter
GovernorCentrifugal governor
Charging systemAlternator 12V, 16A
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Cylinder bore:72.0 mm (2.83 in)
Piston stroke:70.0 mm (2.75 in)
Cylinder internal diameter (standard):72.00-72.030 mm (2.8346-2.8358 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: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):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 bracket7.0 Nm; 5.2 ft·lb
Alternator2.0 Nm; 1.5 ft·lb
Armature3.0 Nm; 2.2 ft·lb
Blower housings7.0 Nm; 5.2 ft·lb
Back plate7.0 Nm; 5.2 ft·lb
Breather3.0 Nm; 2.2 ft·lb
Carburetor to manifold7.0 Nm; 5.2 ft·lb
Connecting rod13.0 Nm; 6.9 ft·lb
Crankcase cover17.0 Nm; 12.6 ft·lb
Cylinder head19.0 Nm; 14.1 ft·lb
Cylinder shield7.0 Nm; 5.2 ft·lb
Exhaust manifold17.0 Nm; 12.6 ft·lb
Flywheel nut175.0 Nm; 129.6 ft·lb
Fan Retainer17.0 Nm; 12.6 ft·lb
Governor lever nut8.0 Nm; 5.9 ft·lb
Governor control bracket16.0 Nm; 11.9 ft·lb
Intake manifold to cylinder head16.0 Nm; 11.9 ft·lb
Oil pump7.0 Nm; 5.2 ft·lb
Rewind starter (to blower housing)7.0 Nm; 5.2 ft·lb
Rocker arm lock nut7.0 Nm; 5.2 ft·lb
Rocker arm stud11.0 Nm; 8.2 ft·lb
Starter motor16.0 Nm; 11.9 ft·lb
Starter motor thru bolts6.0 Nm; 4.4 ft·lb
Valve cover3.0 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: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, side-draft carburetor
Ignition system
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 gap0.2-0.3 mm (0.008-0.012 in)
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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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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