Kohler Command PRO CS4

Kohler CS4The Kohler Command PRO CS4 is a 123 cc (7.5 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 CS4 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 CS4 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 56.0 mm (2.2 in) and 50.0 mm (1.97 in), respectively. Compression ratio rating is 8.3:1. The Command PRO CS4 engine produced 4.0 PS (2.9 kW; 4.0 HP) at 3,600 rpm of maximum horsepower and 7.6 N·m (0.8 kg·m, 5.6 ft·lb) at 2,000 rpm of peak torque.

The breakdown of the engine code is as follows:

  • C – Command series
  • S – Slanted cylinder
  • 4 – output power 4.0 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
ModelKohler Command PRO CS4
Type4-stroke, OHV, single cylinder
Displacement123 cm 3 (7.5 cu-in)
Max. horsepower4.0 PS (2.9 kW; 4.0 HP) at 3,600 rpm
Max. torque (crank PTO)7.6 N·m (0.8 kg·m, 5.6 ft·lb) at 2,000 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 capacity3.9 L (1.03 US. gal. 0.86 Imp. gal.)

Cylinder Block and Head

The Kohler Command PRO CS4 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. A 56.0 mm (2.2 in) cylinder bore and 50.0 mm (1.97 in) piston stroke give the Command PRO CS4 engine a total of 123 cc (7.5 cu·in) of displacement. Compression ratio rating is 8.3:1.

Cylinder block
Compression ratio:8.3:1
Bore x Stroke56 X 50 mm (2.2 x 1.97 in)
Sleeve internal diameter56.005-56.015 mm (2.2049-2.2053 in)
Piston skirt outer diameter55.975-55.990 mm (2.2037-2.2043 in)
Number of piston rings (compression / oil):2 / 1
Ring side clearanceTop0.040-0.080 mm (0.0016-0.0031 in)
Second0.020-0.060 mm (0.0008-0.0024 in)
Ring end gapTop0.200-0.400 mm (0.0079-0.0157 in)
Second0.200-0.400 mm (0.0079-0.0157 in)
Oil (side rail)0.200-0.400 mm (0.0079-0.0157 in)
Connecting rod small end ID16.006-16.020 mm (0.6302-0.6307 in)
Connecting rod big end ID28.000-28.015 mm (1.1024-1.103 in)
Piston pin outer diameter16.002-16.013 mm (0.63-0.6304 in)
Crankshaft main journal diameter:52.000 mm (2.0472 in)
Crankpin diameter:27.969-27.984 mm (1.1011-1.1017 in)
Cylinder Head
Valve Arrangement:OHV
Valve head diameter:INTAKE21.000 mm (0.8268 in)
EXHAUST19.000 mm (0.748 in)
Stem outer diameter (standard):INTAKE5.500 mm (0.2165 in)
EXHAUST5.500 mm (0.2165 in)
Valve length (standard):INTAKE64.500 mm (2.5394 in)
EXHAUST64.500 mm (2.5394 in)
Camshaft journal diameter:14.950 mm (0.5886 in)
Cam height:INTAKE26.850-26.950 mm (1.0571-1.061 in)
EXHAUST26.630-26.730 mm (1.0484-1.0524 in)

Tightening torque specs

Tightening torque specs
Cylinder head bolt20 Nm; 2.0 kg·m; 14 ft·lb
Flywheel65 Nm; 6.5 kg·m; 48 ft·lb
Oil drain plug17 Nm; 1.73 kg·m; 12.5 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 capacity0.6 L (0.63 US. qt, 0.53 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.

ATTENTION! Dear visitors, this site is not a trading platform, an official dealer or a spare parts supplier, so we do not have any price lists or spare parts catalogs. We are an information portal and provide the technical specifications of gasoline and diesel engines.

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.

Be the first to comment

Leave a Reply

Your email address will not be published.