The Kohler M18 is a 691 cc (42.18 cu·in) two-cylinder air-cooled four-stroke internal combustion gasoline engine from the Magnum-series, manufactured by Kohler Co.
The Kohler M18 engine has an L-head (side valve) design and a horizontal PTO shaft. This engine is equipped with the Kohler or two types of Walbro-build carburetor (with fixed main jet or with adjustable mian or high speed needle) and an electronic magneto ignition system. The M18 engine used a high-density paper air cleaner.
The cylinder bore is 79.25 mm (3.12 in) and the piston stroke is 69.85 mm (2.75 in). The compression ratio rating is 6.0:1. This engine produced 18.2 PS (13.4 kW; 18.0 HP) at 3,600 rpm of horsepower.
The breakdown of the engine code is as follows:
- M – M-series
- 18 – 18.0 HP horsepower
- Suffix (engine is available with the following options):
S – Electric starter;
G – Tapered crankshaft (Generator applications);
P – Threaded crankshaft (Pump applications);
EP – Generator;
Q – Quilet model;
General information
| Engine Specifications | |
| Model | M18 |
| Type | 4-stroke, L-head, two-cylinder |
| Displacement | 691 cm 3 (42.18 cu-in) |
| Max. horsepower | 18.2 PS (13.4 kW; 18.0 HP) at 3,600 rpm |
| Max. torque (crank PTO) | – |
| Fuel system | Walbro-build carburetor |
| Cooling system | Forced-air |
| Ignition system | Electronic magneto ignition system |
| Lubricating system | Full-pressure |
| Starting system | Electric starter |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Weight | 59.0 kg (130 lbs) |
Cylinder Block and Head
| Cylinder block | ||
| Compression ratio: | 6.0:1 | |
| Bore x Stroke | 79.25 mm X 69.85 mm (3.12 x 2.75 in) | |
| Sleeve internal diameter | 79.362-79.388 mm (3.1245-3.1255 in) | |
| Piston skirt outer diameter | 79.256-79.273 mm (3.1203-3.1210 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Ring end gap | Top | 0.253-0.582 mm (0.010-0.023 in) |
| Second | 0.253-0.582 mm (0.010-0.023 in) | |
| Piston pin outer diameter | 15.867-15.872 mm (0.6247-0.6249 in) | |
| Main bearing surface (max) | 44.213 mm (1.7407 in) | |
| Crankpin outer diemeter | 34.882-34.895 mm (1.3733-1.3738 in) | |
| Cylinder Head | ||
| Valve Arrangement: | L-head (sidevalve) | |
| Valves: | 2 | |
| Valve minimum lift – Zero lash: | INTAKE | 6.9 mm (0.274 in) |
| EXHAUST | 6.9 mm (0.274 in) | |
| Stem outer diameter (standard): | INTAKE | 7.881 mm (0.3103 in) |
| EXHAUST | 7.843 mm (0.3088 in) | |
Tightening torque specs
| Tightening torque specs | |
| Cylinder head bolt | 20-37 Nm; 2.04-3.77 kg·m; 14.8-27.3 ft·lb |
| Spark plug | 18 N·m; 1.8 kg·m; 13.3 ft·lb |
Service Information
| Engine | |
| Max speed | 3,600 rpm |
| Valve clearance | |
| Intake valve clearance | 0.076-0.152 mm (0.003-0.006 in) |
| Exhaust valve clearance |
S/n 1816500646 and earlier: 0.406-0.482 mm (0.016-0.019 in) S/n 1816500656 and later: 0.278-0.354 mm (0.011-0.014 in) |
| Oil system | |
| Oil type | API SF or SG |
| Recommended oil |
Summer: SAE 30W Winter: SAE 5W-20, 5W-30 |
| Oil capacity (with filter) |
With oil filter: 1.6 L (1.69 US. qt, 1.41 Imp. qt.) W/o oil filter: 1.4 L (1.48 US. qt, 1.23 Imp. qt.) |
| Ignition system | |
| Spark plug | Champion: RV17YC |
| Spark plug gap | 0.89 mm (0.035 in) |
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