The Briggs and Stratton 28Q777 is a 465 cc, (28.4 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 87.3 mm (3.44 in) and 77.7 mm (3.06 in), respectively. The B&S 28Q777 engine produced 15.6 PS (11.5 kW; 15.5 HP) at 3,300 rpm of maximum horsepower.
The B&S 28Q777 features:
- Cast iron sleeve
- OHV (overhead valve) design
- Plain bearing
- Electronic ignition system
- Float type carburetor
- Centrifugal governor
- Full pressure lubrication system
- Forced air cooling system
- Electric starter
General information
| Engine Specifications | |
| Engine model | 28Q777 |
| Engine type | 4-stroke, OHV, single-cylinder |
| Displacement | 465 cm3, (28.38 cu·in) |
| Max. horsepower | 15.6 PS (11.5 kW; 15.5 HP) at 3,300 rpm |
| Max. torque | – |
| Cooling system | Forced air |
| Air cleaner | Paper filter with a foam pre-cleaner |
| Lubricating system | Full pressure lubrication system |
| Ignition system | Electronic |
| Fuel system | Float type carburetor |
| Fuel consumption | |
| Fuel used | Gasoline |
| Starting system | Electric starter |
| Governor | Centrifugal governor |
| Dimensions (L x W X H) | – |
| Dry weight | – |
Cylinder Block and Head
| Cylinder block | |
| Compression ratio: | – |
| Cylinder bore: | 87.3 mm (3.44 in) |
| Piston stroke: | 77.7 mm (3.06 in) |
| Cylinder internal diameter (standard): | 87.300-87.400 mm (3.437-3.4409 in) |
| Number of piston rings (compression / oil): | 2/1 |
| Connecting rod big end diameter (standard): | 31.760-31.810 mm (1.2504-1.2524 in) |
| Connecting rod small end diameter (standard): | 20.330-20.370 mm (0.8004-0.802 in) |
| Piston pin diameter: | 20.290-20.310 mm (0.7988-0.7996 in) |
| Side clearance (Top): | 0.03-0.07 mm (0.0012-0.0028 in) |
| Side clearance (Second): | 0.03-0.07 mm (0.0012-0.0028 in) |
| Side clearance (Oil): | 0.03-0.07 mm (0.0012-0.0028 in) |
| Ring end gap (Top): | 0.15-0.35 mm (0.0059-0.0138 in) |
| Ring end gap (Second): | 0.15-0.35 mm (0.0059-0.0138 in) |
| Ring end gap (Oil): | 0.35-0.70 mm (0.0138-0.0276 in) |
| Crankshaft main journal diameter: | 34.950 mm (1.376 in) |
| Crankpin journal diameter: | 31.690-31.720 mm (1.2476-1.2488 in) |
| Crankshaft center distance: | 38.85 mm (1.53 in) |
| Cylinder head | |
| Valve arrangement: | OHV (overhead valve), gear driven |
| Valves: | 2 |
| Valve steam diameter (INTAKE): | 5.960-5.980 mm (0.2346-0.2354 in) |
| Valve steam diameter (EXHAUST): | 5.960-5.980 mm (0.2346-0.2354 in) |
| Camshaft lobe height (INTAKE): | 21.02 mm (0.8276 in) |
| Camshaft lobe height (EXHAUST): | 21.02 mm (0.8276 in) |
Tightening torque
| 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 |
| Blower housing brackets | 10.0 Nm; 7.4 ft·lb |
| Breather | 4.0 Nm; 2.9 ft·lb |
| Carburetor to intake manifold | 7.0 Nm; 5.2 ft·lb |
| Connecting rod | 21.0 Nm; 15.6 ft·lb |
| Control bracket | 5.0 Nm; 3.7 ft·lb |
| Crankcase cover | 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 | 5.0 Nm; 3.7 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 | 19.0 Nm; 14.1 ft·lb |
| Oil drain plug | 14.0 Nm; 10.4 ft·lb |
| Oil pump cover | 10.0 Nm; 7.4 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 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 |
| Spark plug: | Champion RJ19LM |
| 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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