The Kohler K321 is a 512 cc, (31.2 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.
Cylinder bore and piston stroke are 88.9 mm (3.5 in) and 82.6 mm (3.25 in), respectively. This engine produced 14.1 PS (10.4 kW; 14.0 HP) at 3,600 rpm of horsepower.
The Kohler K321 features:
- L-head (side valve) design
- Magneto ignition system, battery ignition system, breakerless ignition system ignition system*
- Carburetor (Kohler or Walbro – fixed main jet or adjustable main jet)*
- Centrifugal governor
- Splash type lubrication system
- Forced air cooling system
- Retractable and electric starter
* – depending on modification
General information
| Engine Specifications | |
| Engine model | K321 |
| Engine type | 4-stroke, L-head (side valve), single-cylinder |
| Displacement | 512 cm3, (31.24 cu·in) |
| Max. horsepower | 14.1 PS (10.4 kW; 14.0 HP) at 3,600 rpm |
| Max. torque | – |
| Cooling system | Forced air |
| Air cleaner | Paper air cleaner (oiled foam precleaner) |
| Lubricating system | Splash type |
| Ignition system | Magneto ignition system, battery ignition system, breakerless ignition system |
| Fuel system | Carburetor (Kohler or Walbro – fixed main jet or adjustable main jet) |
| Fuel consumption | – |
| Fuel tank capacity | – |
| Fuel used | Unleaded gasoline (octane number 86 or higher) |
| Starting system | Retractable or electric starter |
| Governor | Centrifugal governor |
| PTO shaft rotation | Counterclockwise (from PTO shaft side) |
| Dimensions (L x W X H) | – |
| Dry weight | 53.5 kg (117.9 lbs) |
Cylinder Block and Head
| Cylinder block | |
| Compression ratio: | – |
| Cylinder bore: | 88.9 mm (3.5 in) |
| Piston stroke: | 82.6 mm (3.25 in) |
| Cylinder internal diameter (standard): | 88.9127-88.8873 mm (3.5005-3.4995 in) |
| Piston skirt outer diameter (standard): | 88.7501-88.7425 mm (3.4941-3.4938 in) |
| Number of piston rings (compression / oil): | 2/1 |
| Connecting rod small end diameter (standard): | 22.2428-22.2504 mm (0.8757-0.876 in) |
| Piston pin diameter: | 22.2300-22.2352 mm (0.8752-0.8754 in) |
| Ring end gap (Top): | 0.177-0.432 mm (0.007-0.017 in) |
| Ring end gap (Second): | 0.177-0.432 mm (0.007-0.017 in) |
| Crankshaft center distance: | 41.3 mm (1.625 in) |
| Cylinder head | |
| Valve arrangement: | L-head (side valve), belt driven |
| Valves: | 2 |
| Valve head diameter (INTAKE): | 34.798-35.052 mm (1.37-1.38 in) |
| Valve head diameter (EXHAUST): |
28.448-28.702 mm (1.12-1.13 in) Suffix “D” and later: 34.798-35.052 mm (1.370-1.380 in) |
| Valve steam diameter (INTAKE): | 7.8867-7.8994 mm (0.3105-0.311 in) |
| Valve steam diameter (EXHAUST): | 7.8334-7.8511 mm (0.3084-0.3091 in) |
Service Data
| Engine | |
| Maximum speed: | 3,600 rpm |
| 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 type |
| Oil type: | SF or SG |
| Recommended oil: |
Summer: SAE 30W Winter: SAE 5W-20, 5W-30 |
| Oil capacity: |
K321: 1.9 L (2.01 US. qt, 1.67 Imp. qt.) K321A: 1.2 L (1.27 US. qt, 1.06 Imp. qt.) |
| Fuel system | |
| Type: | Carburetor (Kohler or Walbro – fixed main jet or adjustable main jet) |
| Ignition system | |
| Type: | Magneto ignition system, battery ignition system, breakerless 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) |