The Briggs and Stratton 42A707 is a 694 cc (42.35 cu·in) two-culinder air-cooled four-stroke internal combustion gasoline engine, manufactured by Briggs and Stratton.
The B&S 42A707 engine has an L-head (side valve) design and a vertical PTO shaft. This engine is equipped with float type carburetor and a flywheel magneto ignition system. The B&S 42A707 engine used a full pressure lubrication system.
A 87.3 mm (3.44 in) cylinder bore and 58.0 mm (2.28 in) piston stroke give the B&S 42A707 engine a total of 694 cc of displacement.
This engine produced 18.1 PS (13.3 kW; 18.0 HP) at 3,600 rpm of horsepower and 38.7 N·m (3.9 kg·m, 28.4 ft·lb) at 2,600 rpm of torque.
The breakdown of the engine code is as follows:
- 42 – Displacement
- A – Basic design series
- 7 – Vertical PTO-shaft
- 0 – Ball bearing
- 7 – Electric starter
General information
| Engine Specifications | |
| Model | B&S 42A707 |
| Type | 4-stroke, L-head, opposed-twin |
| Displacement | 694 cm 3 (42.3 cu-in) |
| Max. horsepower | 18.1 PS (13.3 kW; 18.0 HP) at 3,600 rpm |
| Max. torque | 38.7 N·m (3.9 kg·m, 28.4 ft·lb) at 2,600 rpm |
| Fuel system | Float type carburetor |
| Cooling system | Forced-air |
| Ignition system | Flywheel magneto |
| Lubricating system | Full pressure lubrication |
| Starting system | Electric starter |
| Fuel used | Gasoline |
| Fuel tank capacity | – |
Cylinder Block and Head
| Cylinder block | ||
| Bore x Stroke | 87.3 mm X 58.0 mm (3.44 x 2.28 in) | |
| Sleeve internal diameter | 87.280-87.310 mm (3.4362-3.4374 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Side clearance | Top | 0.090-0.150 mm (0.0035-0.0059 in) |
| Second | 0.090-0.150 mm (0.0035-0.0059 in) | |
| Oil | 0.090-0.150 mm (0.0035-0.0059 in) | |
| Ring end gap | Top | 0.180-0.430 mm (0.0071-0.0169 in) |
| Second | 0.180-0.430 mm (0.0071-0.0169 in) | |
| Oil | 0.180-0.430 mm (0.0071-0.0169 in) | |
| Connecting rod small end ID | 20.340-20.350 mm (0.8008-0.8012 in) | |
| Piston pin outer diameter | 20.320-20.330 mm (0.8000-0.8004 in) | |
| Cylinder Head | ||
| Valve Arrangement: | L-head | |
| Valves: | 4 (2 per cylinder) | |
| Valve steam diameter | INTAKE | 7.820-7.870 mm (0.3079-0.3098 in) |
| EXHAUST | 7.820-7.870 mm (0.3079-0.3098 in) | |
Tightening torque
| Tightening torque specs | |
| Alternator (to cylinder) | 2.0 Nm; 1.5 ft·lb |
| Air cleaner base (to carburetor) | 3.0 Nm; 2.2 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 | 11.0 Nm; 8.1 ft·lb |
| Connecting rod | 22.0 Nm; 16.3 ft·lb |
| Crankcase sump/cover | 25.0 Nm; 18.5 ft·lb |
| Cylinder head | 18.0 Nm; 13.3 ft·lb |
| Carburetor to solenoid | 11.0 Nm; 8.1 ft·lb |
| Fan Retainer | 17.0 Nm; 12.6 ft·lb |
| Flywheel nut | 203.0 Nm; 150.0 ft·lb |
| Governor lever nut | 11.0 Nm; 8.1 ft·lb |
| Intake manifold to cylinder head | 10.0 Nm; 7.4 ft·lb |
| Starter motor | 18.0 Nm; 13.3 ft·lb |
Service Information
| Engine | |
| Max speed | 3,600 rpm |
| Valve clearance | |
| Intake valve clearance | 0.15-0.20 mm (0.006-0.008 in) |
| Exhaust valve clearance | 0.23-0.28 mm (0.009-0.011 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) | 1.70 L (1.8 US. qt, 1.5 Imp. qt.) |
| Ignition system | |
| Spark plug | Champion RJ-12, AC R-46, Autolite 308 |
| Spark plug gap | 0.7-0.8 mm (0.0276-0.0315 in) |
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