Briggs and Stratton 28R707

Briggs and Stratton 28R707The Briggs and Stratton 28R777 is a 465 cc (28.4 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine, manufactured by Briggs and Stratton.

The B&S 28R707 engine has an L-head (side valve) design and a vertical PTO shaft. This engine is equipped with float type carburetor and an electronic ignition system. The B&S 28R707 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 13.6 PS (10.0 kW; 13.5 HP) at 3,300 rpm of horsepower.

The breakdown of the engine code is as follows:

  • 28 – Displacement
  • R – Basic design series
  • 7 – Vertical PTO-shaft
  • 0 – Plain bearing
  • 7 – Electric starter

General information

Engine Specifications
ModelB&S 28R707
Type4-stroke, L-head, single-cylinder
Displacement465 cm 3 (28.38 cu-in)
Max. horsepower13.6 PS (10.0 kW; 13.5 HP) at 3,300 rpm
Max. torque
Fuel systemCarburetor
Cooling systemForced-air
Ignition systemElectronic
Lubricating system
Starting systemElectric starter
Fuel usedGasoline
Fuel tank capacity

Cylinder Block and Head

Cylinder block
Compression ratio:
Bore x Stroke87.3 mm X 77.7 mm (3.44 x 3.06 in)
Sleeve internal diameter87.300-87.400 mm (3.437-3.4409 in)
Number of piston rings (compression / oil):2 / 1
Side clearanceTop0.03-0.07 mm (0.0012-0.0028 in)
Second0.03-0.07 mm (0.0012-0.0028 in)
Oil0.03-0.07 mm (0.0012-0.0028 in)
Ring end gapTop0.15-0.35 mm (0.0059-0.0138 in)
Second0.15-0.35 mm (0.0059-0.0138 in)
Oil0.35-0.70 mm (0.0138-0.0276 in)
Connecting rod small end ID20.330-20.370 mm (0.8004-0.802 in)
Piston pin outer diameter20.290-20.310 mm (0.7988-0.7996 in)
Cylinder Head
Valve Arrangement:L-head (sidevalve)
Valve steam diameterINTAKE5.960-5.980 mm (0.235-0.235 in)
EXHAUST5.960-5.980 mm (0.235-0.235 in)

Tightening torque specs

Tightening torque specs
Air cleaner base6.0 Nm; 4.4 ft·lb
Alternator2.0 Nm; 1.5 ft·lb
Armature3.0 Nm; 2.2 ft·lb
Blower housings10.0 Nm; 7.4 ft·lb
Blower housing brackets10.0 Nm; 7.4 ft·lb
Breather4.0 Nm; 2.9 ft·lb
Carburetor to intake manifold7.0 Nm; 5.2 ft·lb
Connecting rod21.0 Nm; 15.6 ft·lb
Control bracket5.0 Nm; 3.7 ft·lb
Crankcase cover25.0 Nm; 18.5 ft·lb
Cylinder head25.0 Nm; 18.5 ft·lb
Cylinder shield5.0 Nm; 3.7 ft·lb
Exhaust manifold / adapter19.0 Nm; 14.0 ft·lb
Flywheel nut135.0 Nm; 100.0 ft·lb
Flywheel fan16.0 Nm; 11.9 ft·lb
Fuel pump5.0 Nm; 3.7 ft·lb
Governor lever nut5.0 Nm; 3.7 ft·lb
Intake manifold to cylinder head10.0 Nm; 7.4 ft·lb
Muffler19.0 Nm; 14.1 ft·lb
Oil drain plug14.0 Nm; 10.4 ft·lb
Oil pump cover10.0 Nm; 7.4 ft·lb
Starter motor16.0 Nm; 11.9 ft·lb

Service Information

Max speed3,600 rpm
Valve clearance
Intake valve clearance0.08-0.13 mm (0.003-0.005 in)
Exhaust valve clearance0.13-0.18 mm (0.005-0.007 in)
Oil system
Oil typeAPI 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 plugChampion RJ19LM
Spark plug gap0.7-0.8 mm (0.0276-0.0315 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.

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