The Kohler M20 is a 770 cc (46.98 cu·in) two-cylinder air-cooled four-stroke internal combustion gasoline engine from the Magnum-series, manufactured by Kohler Co.
The Kohler Magnum 20 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 M20 engine used a high-density paper air cleaner.
The cylinder bore is 79.25 mm (3.12 in) and the piston stroke is 77.7 mm (3.06 in). The compression ratio rating is 6.6:1.
This engine produced 20.3 PS (14.9 KW; 20.0 HP) at 3,600 rpm of horsepower.
The breakdown of the engine code is as follows:
- M – M-series
- 20 – 20.0 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 | Magnum M20 |
Type | 4-stroke, L-head, two-cylinder |
Displacement | 770 cm 3 (46.98 cu-in) |
Max. horsepower | 20.3 PS (14.9 KW; 20.0 HP) at 3,600 rpm |
Max. torque (crank PTO) | – |
Fuel system | Kohler or Walbro 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: | 6.6:1 | |
Bore x Stroke | 79.25 mm X 77.7 mm (3.12 x 3.06 in) | |
Sleeve internal diameter | 79.362-79.388 mm (3.1245-3.1255 in) | |
Piston skirt outer diameter | 79.268-79.286 mm (3.1208-3.1215 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 | 19.047-19.052 mm (0.7499-0.7501 in) | |
Main bearing surface (max) | 44.213 mm (1.7407 in) | |
Crankpin outer diemeter | 38.082-38.095 mm (1.4993-1.4998 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) |
We try to use verified sources and official documentation, however, differences between sources or errors in entering information may occur. We do not provide advice on technical issues related to the engines operation or repair. We do not recommend using provided information for engines repairing engines or spare parts ordering, use only official service manuals and spare-parts catalogs.
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