The Kohler M12 is a 476 cc, (29.07 cu·in) natural aspirated single-cylinder four-stroke air-cooled internal combustion small gasoline engine with a horizontal shaft, manufactured by Kohler Co for general-purpose applications.
The cylinder bore is 85.85 mm (3.38 in) and the piston stroke is 82.6 mm (3.25 in). The compression ratio rating is 6.6:1.
The Kohler M12 engine produced 12.1 PS (8.9 KW; 12.0 HP) at 3,600 rpm of maximum output power.
The Kohler M12 features:
- L-head (side valve) design
- Electronic magneto ignition system
- Side-draft carburetor
- Centrifugal type governor
- Splash lubrication system
- Forced air cooling system
- Recoil or electric starter
The Kohler Magnum 12 suffix (engine is available with the following options):
- S – Electric starter;
- T – Retractable starter;
- ST – Electric and retractable starter;
- G – Tapered crankshaft (Generator applications);
- P – Threaded crankshaft (Pump applications);
- R – Reduction gear unit;
- EP – Generator;
General information
| Engine Specifications | |
| Engine model | Magnum M12 |
| Engine type | 4-stroke, L-head, single-cylinder |
| Displacement | 476 cm3, (29.07 cu·in) |
| Max. horsepower | 12.1 PS (8.9 KW; 12.0 HP) at 3,600 rpm |
| Max. torque | – |
| Cooling system | Forced air |
| Air cleaner | High-density paper |
| Lubricating system | Splash |
| Ignition system | Electronic magneto ignition system |
| Fuel system | Side-draft carburetor with adjustable jet |
| Fuel tank capacity | 5.7 liters (1.5 US gal, 1.3 Imp. gal) |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Starting system | Recoil or electric starter |
| Governor | Centrifugal governor |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
| Dry weight | 58.5 kg (129.0 lbs) |
Cylinder Block and Head
| Cylinder block | |
| Compression ratio: | 6.6:1 |
| Cylinder bore: | 85.8 mm (3.38 in) |
| Piston stroke: | 82.6 mm (3.25 in) |
| Cylinder internal diameter (standard): | 85.7123-85.7377 mm (3.3745-3.3755 in) |
| Piston skirt outer diameter (standard): | 85.4710-85.5472 mm (3.3650-3.3680 in) |
| Number of piston rings (compression / oil): | 2/1 |
| Connecting rod small end diameter (standard): | 22.2428-2.2505 mm (0.8757-0.8760 in) |
| Piston pin diameter: | 22.2377-22.2351 mm (0.8752-0.8754 in) |
| Side clearance (Top): | 0.152 mm (0.006 in) |
| Side clearance (Second): | 0.152 mm (0.006 in) |
| Ring end gap (Top): | 0.254-0.508 mm (0.010-0.020 in) |
| Ring end gap (Second): | 0.254-0.508 mm (0.010-0.020 in) |
| Crankpin journal diameter: | 38.0873-38.1000 mm (1.4995-1.5000 in) |
| Crankshaft main bearing surface outer diameter: | 39.9923-40.0025 mm (1.5745-1.5749 in) |
| Cylinder head | |
| Valve arrangement: | L-head (side valve) |
| Valves: | 2 |
| Valve head diameter (INTAKE): | 34.798-35.052 mm (1.370-1.380 in) |
| Valve head diameter (EXHAUST): | 28.448-28.702 mm (1.120-1.130 in) |
| Valve seat angle (INTAKE): | 89° |
| Valve seat angle (EXHAUST): | 89° |
| Valve seat angle (INTAKE): | 45° |
| Valve seat angle (EXHAUST): | 45° |
| Valve steam min diameter (INTAKE): | 7.8816 mm (0.3103 in) |
| Valve steam min diameter (EXHAUST): | 7.8079 mm (0.3074 in) |
| Valve minimum lift, zero lash (INTAKE): | 8.07 mm (0.318 in) |
| Valve minimum lift, zero lash (EXHAUST): | 8.07 mm (0.318 in) |
Service Data
| Valve clearance | |
| Intake valve clearance: | 0.20-0.25 mm (0.0079-0.0098 in) |
| Exhaust valve clearance: | 0.43-0.48 mm (0.0169-0.0189 in) |
| Oil system | |
| Lubrication system: | Splash |
| Oil type: | API SF or SG |
| Recommended oil: | Summer: SAE 30 Winter: SAE 5W-20, 5W-30 |
| Oil capacity: | 1.9 L (2.00 US. qt, 1.67 Imp. qt.) |
| Fuel system | |
| Type: | Side-draft carburetor |
| Preliminary main fuel screw setting: | 2-1/2 turns |
| Preliminary idle fuel screw setting: | 2-1/2 turns |
| Float level: | 11/64 ± 1/32 |
| Float drop: | 1-1/32 |
| Ignition system | |
| Type: | Electronic magneto ignition system |
| Spark plug: | Champion RH10 |
| Spark plug gap: | 0.65 mm (0.0256 in) |
| Spark plug torque: | 27 N·m (2.8 kg·m, 19.9 ft·lb) |
| Ignition coil air gap | 0.30-0.40 mm (0.012-0.016 in) |
References
1. Kohler Magnum M8, M10, M12, M14, M16 single cylinder engine service manual. Kohler Co.
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