The 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 model | 331777 Intek |
| Engine type | 4-stroke, OHV, single-cylinder |
| Displacement | 540 cm3, (32.9 cu·in) |
| Max. horsepower | 20.3 PS (14.9 kW; 20.0 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) |
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