Kohler Command PRO CS12

Kohler Command PRO CS12The Kohler Command PRO CS12 is a 357 cc (21.8 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine from Command PRO series, manufactured by Kohler Co., for general-purpose applications, such as construction and industrial equipment, portable generators, commercial or residential lawn, and garden equipment.

The Kohler CS12 engine has an OHV (overhead valve) design, cast iron cylinder liners, aluminum block, steel-forged horizontal shaft, and dual main ball bearings. This engine is equipped with fixed jet Mikuni carburetor, electronic TCI (Transistor Controlled Ignition) system, mechanical governor and automatic compression release. The Command PRO CS12 engine can be equipped with one of three air cleaner configurations: the standard dual-element air cleaner, heavy-duty cyclonic air cleaner (option), or an oiled, solid foam element (option).

Cylinder bore and piston stroke are 85.0 mm (3.35 in) and 63.0 mm (2.48 in), respectively. Compression ratio rating is 8.1:1. The Command PRO CS12 engine produced 12.2 PS (8.95 kW; 12.0 HP) at 3,600 rpm of horsepower and 22.6 N·m (2.3 kg·m, 16.7 ft·lb) at 2,000 rpm of torque for engines with spec 9415xx, and 24.9 Nm (2.54 kg·m; 18.38 ft·lb) at 2,400 rpm for engines with spec 9416xx.

The breakdown of the engine code is as follows:

  • C – Command series
  • S – Slanted cylinder
  • 12 – output power 12.0 HP
  • Suffix (engine is available with the following options):
    S – Electric starter;
    T – Retractable starter;
    G – Tapered crankshaft;
    P – Threaded crankshaft;
    R – Gear Reduction (2:1 or 6:1);

General information

Engine Specifications
ModelCommand PRO CS12
Type4-stroke, OHV, single cylinder
Displacement357 cm 3 (21.8 cu-in)
Max. horsepower12.2 PS (8.95 kW; 12.0 HP) at 3,600 rpm
Max. torque (crank PTO) Spec 9415xx: 22.6 N·m (2.3 kg·m, 16.7 ft·lb) at 2,000 rpm
Spec 9416xx: 24.9 Nm (2.54 kg·m; 18.38 ft·lb) at 2,400 rpm
Fuel systemCarburetor wit fixed jet (Mikuni)
Cooling systemForced-air
Ignition systemTCI (Transistor Controlled Ignition)
Lubricating systemSplash type
Starting systemRecoil or electric starter
Fuel usedUnleaded gasoline (octane number 86 or higher)
Fuel tank capacity6.9 L (1.82 US. gal. 1.52 Imp. gal.)

Cylinder Block and Head

The Kohler Command PRO CS12 has aluminum cylinder block with cast iron cylinder liner, dual ball bearing supported forged steel crankshaft. The piston has two compression rings and one oil ring. An 85.0 mm (3.35 in) cylinder bore and 63.0 mm (2.48 in) piston stroke give the Command PRO CS12 engine a total of 357 cc (20.8 cu·in) of displacement. Compression ratio rating is 8.1:1.

Cylinder block
Compression ratio:8.1:1
Bore x Stroke85.0 X 63.0 mm (3.35 x 2.48 in)
Sleeve internal diameter85.000-85.020 mm (3.3465-3.3472 in)
Piston skirt outer diameter84.954-84.998 mm (3.3446-3.3464 in)
Number of piston rings (compression / oil):2 / 1
Ring side clearanceTop0.040-0.080 mm (0.0016-0.0031 in)
Second0.030-0.070 mm (0.0012-0.0028 in)
Ring end gapTop0.250-0.400 mm (0.0098-0.0157 in)
Second0.250-0.400 mm (0.0098-0.0157 in)
Oil (side rail)0.200-0.700 mm (0.0079-0.0276 in)
Connecting rod small end ID20.006-20.020 mm (0.7876-0.7882 in)
Connecting rod big end ID36.000-36.015 mm (1.4173-1.4179 in)
Piston pin outer diameter19.995-20.000 mm (0.7872-0.7874 in)
Crankshaft main journal diameter:72.000 mm (2.8346 in)
Crankpin diameter:35.969-35.984 mm (1.4161-1.4167 in)
Cylinder Head
Valve Arrangement:OHV
Valve head diameter:INTAKE32.000 mm (1.2598 in)
EXHAUST27.000 mm (1.063 in)
Stem outer diameter (standard):INTAKE6.000-6.012 mm (0.2362-0.2367 in))
EXHAUST6.000-6.012 mm (0.2362-0.2367 in)
Valve length (standard):INTAKE88.100 mm (3.4685 in)
EXHAUST87.900 mm (3.4606 in)
Camshaft journal diameter:15.965-15.990 mm (0.6285-0.6295 in)
Cam height:INTAKE32.500-32.600 mm (1.2795-1.2835 in)
EXHAUST32.500-32.600 mm (1.2795-1.2835 in)

Tightening torque specs

Tightening torque specs
Cylinder head bolt50 Nm; 5.1 kg·m; 37 ft·lb
Flywheel120 Nm; 12.2 kg·m; 88 ft·lb
Oil drain plug20 Nm; 2.0 kg·m; 14.8 ft·lb
Spark plug20 N·m (2 kg·m, 14.7 ft·lb)

Service Information

Idle speed2,000 ± 150 rpm
Cylinder compression4.0-6.0 kg/cm2 (400-600 kPa, 57-85 psi) at 600 rpm
Valve clearance
Intake valve clearance0.10 mm (0.0039 in)
Exhaust valve clearance0.10 mm (0.0039 in)
Oil system
Oil typeAPI SG, SH, SJ or higher
Recommended oilSAE 10W-30
Oil capacity1.1 L (1.16 US. qt, 0.97 Imp. qt.)
Ignition system
Spark plugNGK: BPR4ES, Champion: RN14YC, RC14YC
Spark plug gap0.8 mm (0.0315 in)
Ignition module air gap0.4-0.6 mm (0.015-0.023 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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