Kohler K321

Kohler K321The 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)