Briggs and Stratton 351777

Briggs and Stratton 351777The Briggs and Stratton 351777 Vanguard is a 570 cc (34.8 cu·in) V-twin air-cooled four-stroke internal combustion gasoline engine, manufactured by Briggs and Stratton.

The B&S 351777 engine has an OHV (overhead valve) design and a vertical PTO shaft. This engine is equipped with float type, side-draft carburetor and an magneto electronic ignition system. The B&S 351777 engine used Dual-Clean air cleaner (paper element with a foam pre-cleaner).

The cylinder bore is 72.0 mm (2.83 in) and the piston stroke is 70.0 mm (2.75 in). This engine produced 20.1 PS (14.8 KW; 20.0 HP) at 3,600 rpm of horsepower.

The breakdown of the engine code is as follows:

  • 35 – Displacement
  • 1 – Basic design series
  • 7 – Vertical PTO-shaft
  • 7 – Ball bearing, flange mounting, pressure lubrication
  • 7 – Electric starter

General information

Engine Specifications
Model B&S 351777 Vanguard
Type 4-stroke, L-head, V-twin
Displacement 570 cm 3 (34.8 cu-in)
Max. horsepower 20.1 PS (14.8 KW; 20.0 HP) at 3,600 rpm
Max. torque
Fuel system Float type, side-draft carburetor
Cooling system Forced-air
Ignition system Electronic
Lubricating system Full pressure lubrication with spin-on oil filter
Starting system Electric starter
Fuel used Gasoline
Fuel tank capacity

Cylinder Block and Head

Cylinder block
Bore x Stroke 72.0 mm X 70.0 mm (2.83 x 2.76 in)
Sleeve internal diameter 72.00-72.030 mm (2.8346-2.8358 in)
Number of piston rings (compression / oil): 2 / 1
Side clearance Top 0.045-0.076 mm (0.0018-0.003 in)
Second 0.045-0.076 mm (0.0018-0.003 in)
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)
Second 0.200-0.400 mm (0.0079-0.0157 in)
Oil 0.200-0.400 mm (0.0079-0.0157 in)
Connecting rod small end ID 17.090-17.100 mm (0.6728-0.6732 in)
Piston pin outer diameter 17.070-17.080 mm (0.672-0.6724 in)
Cylinder Head
Valve Arrangement: OHV
Valves: 4 (2 per cylinder)
Valve steam diameter INTAKE 5.950-5.960 mm (0.2343-0.2346 in)
EXHAUST 5.940-5.950 mm (0.2339-0.2343 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 Information

Max speed 3,600 rpm
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
Oil type API SF, SG, SH, SJ or higher
Recommended oil Summer: SAE 30, 10W-30
Winter: SAE 5W-30
Oil capacity (with filter) 1.65 L (1.74 US. qt, 1.45 Imp. qt.)
Ignition system
Spark plug Champion RC12YC
Spark plug gap 0.7-0.8 mm (0.0276-0.0315 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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