Kohler K321

Kohler K321The Kohler K321 is a 512 cc (31.24 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine from K-series, manufactured by Kohler Co.

The Kohler K321 engine has an L-head (side valve) design and horizontal PTO-shaft. This engine can be equipped with Kohler or Walbro carburetor and magneto, battery or breakerless ignition systems. The K321 engine used paper air cleaner (oiled foam pre-cleaner was available as an option).

The cylinder bore is 88.9 mm (3.5 in) and the piston stroke is 82.6 mm (3.25 in). This engine produced 14.1 PS (10.4 kW; 14.0 HP) at 3,600 rpm of horsepower.

The breakdown of the engine code is as follows:

  • K – K-series
  • 32 – Approximate daisplacement (cu·in)
  • 1 – Single cylinder
  • Suffix (engine is available with the following options):
    S – Electric starter;
    T – Retractable starter;
    ST – Electric and retractable starter;
    EP – Electric plant;
    A – Special oil pan;
    C – Clutch model;
    G – Generator applications;
    P – Pump model;
    Q – Quled model;
    R – Reduction gear;

General information

Engine Specifications
Model K321
Type 4-stroke, L-head, single cylinder
Displacement 512 cm 3 (31.24 cu-in)
Max. horsepower 14.1 PS (10.4 kW; 14.0 HP) at 3,600 rpm
Max. torque (crank PTO)
Fuel system Carburetor (Kohler or Walbro, fixed main jet or adjustable main jet)
Cooling system Forced-air
Ignition system Magneto or battery or breakerless ignition system
Lubricating system Splash type
Starting system Recoil or electric starter
Fuel used Unleaded gasoline (octane number 86 or higher)
Fuel tank capacity

Cylinder Block and Head

Cylinder block
Compression ratio:
Bore x Stroke 88.9 X 82.6 mm (3.5 x 3.25 in)
Sleeve internal diameter 88.9127-88.8873 mm (3.5005-3.4995 in)
Piston skirt outer diameter 88.7501-88.7425 mm (3.4941-3.4938 in)
Number of piston rings (compression / oil): 2 / 1
Ring end gap Top 0.177-0.432 mm (0.007-0.017 in)
Second 0.177-0.432 mm (0.007-0.017 in)
Connecting rod small end ID 22.2428-22.2504 mm (0.8757-0.876 in)
Piston pin outer diameter 22.2300-22.2352 mm (0.8752-0.8754 in)
Cylinder Head
Valve Arrangement: L-head (sidevalve)
Valves: 2
Valve head diameter: INTAKE 34.798-35.052 mm (1.370-1.380 in)
EXHAUST 28.448-28.702 mm (1.120-1.130 in)
Suffix “D” and later: 34.798-35.052 mm (1.370-1.380 in)
Stem outer diameter (standard): INTAKE 7.887-7.899 mm (0.3105-0.3110 in)
EXHAUST 7.833-7.851 mm (0.3084-0.3091 in)

Tightening torque specs

Tightening torque specs
Cylinder head bolt 34-41 Nm; 3.5-4.2 kg·m; 25-30 ft·lb
Flywheel Nut: 68-81 Nm; 6.98.2 kg·m; 50-60 ft·lb
Screw: 30-35 Nm; 3.0-3.5 kg·m; 22-27 ft·lb
Spark plug 25-30 Nm; 2.55-3.06 kg·m; 18-22 ft·lb

Service Information

Engine
Max 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
Oil type API 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.)
Ignition system
Spark plug Champion: RH10
Spark plug gap 0.65 mm (0.0256 in)
Author: Sergei Wers
About: Co-founder and CEO of a multi-brand auto repair shop (engine repair, chassis repair, body repair and painting) for over 15 years. I have been developing internet sites with technical specifications for more than seven years.

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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.

10 Comments

  1. what is the tighting pattern for a k32114 hp kololer engine an thr proper nut & washer arangement

  2. im looking to purchase a 1991 K321 Wheel Horse mower. Dont need the mower as I would remove the mower deck but will install the snow blade for pushing snow and dirt.
    Is this a good machine and motor to purchase.

    • Yes my old John Deere has k 321 engine, I have about every attachments, tiller, snow thrower, mower deck, blade wheel weights and tire chains. The engine is very powerful compared to a new mobile.

  3. The K321 in my 1970 Cub Cadet 147 does not have a fuel pump, as it is gravity fed. However the K321 in a 1972 J.I. Case 644 FEL (Front End Loader) does have a cam driven mechanical fuel pump. Is there a more detailed description of the variations in these engines (if there are others) that have the same model ID (K321)?

  4. Could you add a starter to a k321 off of a generator? After separating from generator to install into a cub cadet tractor?

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