Briggs and Stratton 331777

Briggs and Stratton 331777The Briggs and Stratton 331777 Intek is a 540 cc (32.9 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 94.0 mm (3.7 in) and 77.8 mm (3.06 in), respectively. This engine produced 20.3 PS (14.9 kW; 20 HP) at 3,600 rpm of horsepower.

The Briggs and Stratton 331777 features:

  • OHV design
  • Cast iron sleeve
  • Electronic ignition system
  • Float type carburetor
  • Centrifugal governor
  • Full pressure lubrication system
  • Forced air cooling system
  • Electric starter 12V

General information

Engine Specifications
Engine model331777 Intek
Engine type4-stroke, OHV, single-cylinder
Displacement540 cm3, (32.9 cu·in)
Max. horsepower20.3 PS (14.9 kW; 20.0 HP) at 3,600 rpm
Max. torque
Cooling systemForced air
Air cleanerPaper filter with a foam pre-cleaner
Lubricating systemFull pressure
Ignition systemElectronic ignition system
Fuel systemFloat type carburetor
Fuel usedGasoline
Starting systemElectric starter 12V
GovernorCentrifugal governor
Dimensions (L x W X H)
Dry weight

Cylinder Block and Head

Cylinder block
Cylinder bore:94.0 mm (3.7 in)
Piston stroke:77.8 mm (3.06 in)
Cylinder internal diameter (standard):94.010-94.110 mm (3.7012-3.7051 in)
Number of piston rings (compression / oil):2/1
Connecting rod big end diameter (standard):27.940-27.990 mm (1.1-1.102 in)
Connecting rod small end diameter (standard):15.890-15.920 mm (0.6256-0.6268 in)
Piston pin diameter:15.850-15.890 mm (0.624-0.6256 in)
Side clearance (Top):0.051-0.076 mm (0.002-0.003 in)
Side clearance (Second):0.051-0.076 mm (0.002-0.003 in)
Side clearance (Oil):0.051-0.076 mm (0.002-0.003 in)
Ring end gap (Top):0.150-0.250 mm (0.0059-0.0098 in)
Ring end gap (Second):0.300-0.510 mm (0.0118-0.0201 in)
Ring end gap (Oil):0.510-0.630 mm (0.0201-0.0248 in)
Crankshaft main journal diameter:41.240 mm (1.6236 in)
Crankpin journal diameter:41.210-41.240 mm (1.6224-1.6236 in)
Crankshaft center distance:38.9 mm (1.53 in)
Cylinder head
Valve arrangement:OHV, gear driven
Valves:2
Valve steam diameter (INTAKE):5.920-5.970 mm (0.2331-0.235 in)
Valve steam diameter (EXHAUST):5.920-5.970 mm (0.2331-0.235 in)
Camshaft lobe height (INTAKE):31.49 mm (1.2398 in)
Camshaft lobe height (EXHAUST):31.49 mm (1.2398 in)
Camshaft journal diameter :12.670 mm (0.4988 in)

Tightening torque specs

Tightening torque specs
Air cleaner base6.0 Nm; 4.4 ft·lb
Alternator2.0 Nm; 1.5 ft·lb
Armature3.0 Nm; 2.2 ft·lb
Blower housings10.0 Nm; 7.4 ft·lb
Breather3.0 Nm; 2.2 ft·lb
Carburetor to intake manifold8.0 Nm; 5.9 ft·lb
Carburetor solenoid5.0 Nm; 3.7 ft·lb
Connecting rod17.0 Nm; 12.6 ft·lb
Control bracket5.0 Nm; 3.7 ft·lb
Crankcase sump25.0 Nm; 18.5 ft·lb
Cylinder head25.0 Nm; 18.5 ft·lb
Cylinder shield5.0 Nm; 3.7 ft·lb
Exhaust manifold / adapter19.0 Nm; 14.0 ft·lb
Flywheel nut135.0 Nm; 100.0 ft·lb
Flywheel fan16.0 Nm; 11.9 ft·lb
Fuel pump10.0 Nm; 7.4 ft·lb
Governor lever nut5.0 Nm; 3.7 ft·lb
Intake manifold to cylinder head10.0 Nm; 7.4 ft·lb
Muffler10.0 Nm; 7.4 ft·lb
Oil drain plug11.0 Nm; 8.1 ft·lb
Oil fill tube10.0 Nm; 7.4 ft·lb
Oil pump cover10.0 Nm; 7.4 ft·lb
Regulator / Rectifier5.0 Nm; 3.7 ft·lb
Rewind starter3.0 Nm; 2.2 ft·lb
Rocker ball set screw or nut5.0 Nm; 3.7 ft·lb
Rocker cover7.0 Nm; 5.2 ft·lb
Starter motor16.0 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 system
Lubrication system:Full pressure
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
TypeFloat type carburetor
Fuel pumpPulse type
Ignition system
Type:Electronic ignition system
Spark plug:Champion RC12YC
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 gap0.25-0.36 mm (0.0098-0.0142 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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