The 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) |
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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