The Briggs and Stratton 28Q777 is a 465 cc (28.38 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine, manufactured by Briggs and Stratton.
The B&S 28Q777 engine has an OHV (overhead valve) design and a vertical PTO shaft. This engine is equipped with float type carburetor and an electronic ignition system. The B&S 28Q777 engine used a paper air filter with a foam pre-cleaner.
The cylinder bore is 87.30 mm (3.44 in) and the piston stroke is 77.7 mm (3.06 in). This engine produced 15.6 PS (11.5 kW; 15.5 HP) at 3,300 rpm of horsepower.
The breakdown of the engine code is as follows:
- 28 – Displacement
- Q – Basic design series
- 7 – Vertical PTO-shaft
- 7 – Plain bearing pressure lubrication
- 7 – Electric starter
General information
| Engine Specifications | |
| Model | B&S 28Q777 |
| Type | 4-stroke, L-head, single-cylinder |
| Displacement | 465 cm 3 (28.38 cu-in) |
| Max. horsepower | 15.6 PS (11.5 kW; 15.5 HP) at 3,300 rpm |
| Max. torque | – |
| Fuel system | Carburetor |
| Cooling system | Forced-air |
| Ignition system | Electronic |
| Lubricating system | Full pressure |
| Starting system | Electric starter |
| Fuel used | Gasoline |
| Fuel tank capacity | – |
Cylinder Block and Head
| Cylinder block | ||
| Compression ratio: | – | |
| Bore x Stroke | 87.3 mm X 77.7 mm (3.44 x 3.06 in) | |
| Sleeve internal diameter | 87.300-87.400 mm (3.437-3.4409 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Side clearance | Top | 0.03-0.07 mm (0.0012-0.0028 in) |
| Second | 0.03-0.07 mm (0.0012-0.0028 in) | |
| 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) |
| Second | 0.15-0.35 mm (0.0059-0.0138 in) | |
| Oil | 0.35-0.70 mm (0.0138-0.0276 in) | |
| Connecting rod small end ID | 20.330-20.370 mm (0.8004-0.802 in) | |
| Piston pin outer diameter | 20.290-20.310 mm (0.7988-0.7996 in) | |
| Cylinder Head | ||
| Valve Arrangement: | OHV (overhead valve) | |
| Valves: | 2 | |
| Valve steam diameter | INTAKE | 5.960-5.980 mm (0.235-0.235 in) |
| EXHAUST | 5.960-5.980 mm (0.235-0.235 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 |
| 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 Information
| Engine | |
| Max speed | 3,600 rpm |
| Valve clearance | |
| Intake valve clearance | 0.08-0.13 mm (0.003-0.005 in) |
| Exhaust valve clearance | 0.13-0.18 mm (0.005-0.007 in) |
| Oil system | |
| Oil type | API SF, SG, SH, SJ or higher |
| Recommended oil |
Summer: SAE 30, 10W-30 Winter: SAE 5W-30 |
| Oil capacity (with filter) | 1.40 L (1.48 US. qt, 1.23 Imp. qt.) |
| Ignition system | |
| Spark plug | Champion RJ19LM |
| Spark plug gap | 0.7-0.8 mm (0.0276-0.0315 in) |
Author:
Champion RJ19LM is NOT the correct spark plug for this engine. The reach is to short.
Yes, I know the information is not correct. The entire Briggs and Stratton engine section is being redesigned and will soon be greatly expanded and errors corrected. Thank you for your comment.
Can you tell me what the correct spark plug is for this engine please?
Thank you
what is the air gap between coil and flywheel