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) |
What is the difference between the 422707 model and the
42A707 model?
I didn’t see a spec for magneto to flywheel gap, does anyone know the factory setting? Thx
Hi Folks Paul from Auckland NZ here, My 42A707 is a transplant into an old Kubota Mower and I decided to put a flexible oil drain hose on it and thought while oil out will change oil filter. no filter to be had…. not there! is it possible to fit an oil filter into the lubrication path on this twin motor. seems can only help…