Briggs and Stratton 281707

The Briggs and Stratton 281707 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 281707 engine has an L-head (side valve) design, cast iron sleeve and a vertical PTO shaft. This engine is equipped with float type carburetor and an electronic ignition system. The B&S 281707 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 12.2 PS (9.0 kW; 12.0 HP) at 3,600 rpm of horsepower.

The breakdown of the engine code is as follows:

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

General information

Engine Specifications
Model	B&S 281707
Type	4-stroke, L-head, single-cylinder
Displacement	465 cm 3 (28.38 cu-in)
Max. horsepower	12.2 PS (9.0 kW; 12.0 HP) at 3,600 rpm
Max. torque	–
Fuel system	Carburetor
Cooling system	Forced-air
Ignition system	Electronic
Lubricating system	Full pressure
Starting system	Electric starter
Fuel used	Unleaded gasoline (octane number 86 or higher)
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	0.05-0.12 mm (0.002-0.0047 in)
	Second	0.05-0.12 mm (0.002-0.0047 in)
	Oil	0.05-0.12 mm (0.002-0.0047 in)
Ring end gap	Top	0.15-0.23 mm (0.0059-0.0091 in)
	Second	0.35-0.45 mm (0.0138-0.0177 in)
	Oil	0.15-0.25 mm (0.0059-0.0098 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:		L-head (sidevalve)
Valves:		2 (4 in total)
Valve steam diameter	INTAKE	5.920-5.970 mm (0.233-0.235 in)
	EXHAUST	5.920-5.970 mm (0.233-0.235 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	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	3.0 Nm; 2.2 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	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
Starter clutch	88.0 Nm; 65.2 ft·lb
Starter motor	16.0 Nm; 11.9 ft·lb
Rocker cover	7.0 Nm; 5.2 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)	1.42 L (1.5 US. qt, 1.25 Imp. qt.)
Ignition system
Spark plug	Champion RJ-19LM
Spark plug gap	0.7-0.8 mm (0.0276-0.0315 in)