Briggs and Stratton 331877

Briggs and Stratton 331877The Briggs and Stratton 331877 Intek Plus Platinum 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 21.4 PS (15.7 KW; 21.0 HP) at 3,600 rpm of horsepower.

The Briggs and Stratton 331877 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 model 331877 Intek Plus Platinum
Engine type 4-stroke, OHV, single-cylinder
Displacement 540 cm3, (32.9 cu·in)
Max. horsepower 21.4 PS (15.7 KW; 21.0 HP) at 3,600 rpm
Max. torque
Cooling system Forced air
Air cleaner Paper filter with a foam pre-cleaner
Lubricating system Full pressure
Ignition system Electronic ignition system
Fuel system Float type carburetor
Fuel used Gasoline
Starting system Electric starter 12V
Governor Centrifugal 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 base 6.0 Nm; 4.4 ft·lb
Alternator 2.0 Nm; 1.5 ft·lb
Armature 3.0 Nm; 2.2 ft·lb
Blower housings 10.0 Nm; 7.4 ft·lb
Breather 3.0 Nm; 2.2 ft·lb
Carburetor to intake manifold 8.0 Nm; 5.9 ft·lb
Carburetor solenoid 5.0 Nm; 3.7 ft·lb
Connecting rod 17.0 Nm; 12.6 ft·lb
Control bracket 5.0 Nm; 3.7 ft·lb
Crankcase sump 25.0 Nm; 18.5 ft·lb
Cylinder head 25.0 Nm; 18.5 ft·lb
Cylinder shield 5.0 Nm; 3.7 ft·lb
Exhaust manifold / adapter 19.0 Nm; 14.0 ft·lb
Flywheel nut 135.0 Nm; 100.0 ft·lb
Flywheel fan 16.0 Nm; 11.9 ft·lb
Fuel pump 10.0 Nm; 7.4 ft·lb
Governor lever nut 5.0 Nm; 3.7 ft·lb
Intake manifold to cylinder head 10.0 Nm; 7.4 ft·lb
Muffler 10.0 Nm; 7.4 ft·lb
Oil drain plug 11.0 Nm; 8.1 ft·lb
Oil fill tube 10.0 Nm; 7.4 ft·lb
Oil pump cover 10.0 Nm; 7.4 ft·lb
Regulator / Rectifier 5.0 Nm; 3.7 ft·lb
Rewind starter 3.0 Nm; 2.2 ft·lb
Rocker ball set screw or nut 5.0 Nm; 3.7 ft·lb
Rocker cover 7.0 Nm; 5.2 ft·lb
Starter motor 16.0 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
Type Float type carburetor
Fuel pump Pulse 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 gap 0.25-0.36 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.

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.

Be the first to comment

Leave a Reply

Your email address will not be published.