Kohler CH255

Kohler CH255The Kohler CH255 is a 177 cc (10.8 cu·in) single-cylinder air-cooled four-stroke internal combustion gasoline engine from the Command PRO series, manufactured by Kohler Co.

The Kohler CH255 engine has an OHV (overhead valve) design, an aluminum block with cast iron cylinder liners, a horizontal PTO-shaft, splash type lubrication system. This engine is equipped with a fixed main jet carburetor and dependable electronic magneto ignition system. Fuel tank capacity is 3.0 liters (3.1 US.qts, 2.6 Imp. qts).

A 68.0 mm (2.70 in) cylinder bore and 49.0 mm (1.90 in) piston stroke give the CH255 engine a total of 177 cc of displacement. The compression ratio rating is 8.5:1.

This engine produces 5.5 PS (4.0 KW; 5.5 HP) at 3,600 rpm of maximum horsepower and 8.3 Nm (0.85 kg·m; 6.13 ft·lb) at 2,800 rpm of peak torque.

The breakdown of the engine code is as follows:

  • C – Command series
  • H – Horizontal PTO shaft
  • 255 – Numerical designation

General information

Engine Specifications
ModelCommand PRO CH255
Type4-stroke, OHV, single-cylinder
Displacement177 cm 3 (10.8 cu-in)
Max. horsepower5.5 PS (4.0 KW; 5.5 HP) at 3,600 rpm
Max. torque8.3 Nm (0.85 kg·m; 6.13 ft·lb) at 2,800 rpm
Fuel systemCarburetor with a fixed main jet
Cooling systemForced-air
Ignition systemDependable electronic magneto
Lubricating systemSplash type
Starting systemRecoil starter
Fuel usedUnleaded gasoline (octane number 86 or higher)
Dimensions (L x W X H)296 x 354 x 318 mm (11.6 x 13.9 x 12.5 in)
Dry weight15.0 kg (33.2 lbs)

Cylinder Block and Head

Cylinder block
Compression ratio:8.5:1
Bore x Stroke68.0 mm X 49.0 mm (2.70 x 1.90 in)
Sleeve internal diameter68.027-68.035 mm (2.6280-2.6785 in)
Number of piston rings (compression / oil):2 / 1
Thrust face outer diameter67.975-67.985 mm (2.6762-2.6766 in)
Piston pin outer diameter17.992-17.995 mm (0.7083-0.7084 in)
Ring-to-groove side clearance:Top0.040-0.150 mm (0.0020-0.0060 in)
Second0.040-0.150 mm (0.0020-0.0060 in)
Oil0.050-0.190 mm (0.0019-0.0075 in)
Ring end gap:Top0.325-0.400 mm (0.0130-0.0160 in)
Second0.325-0.400 mm (0.0130-0.0160 in)
Crankshaft main journal diameter:24.975-24.989 mm (0.9833-0.9838 in)
Crankpin journal diameter:24.975-24.989 mm (0.9833-0.9838 in)
Cylinder Head
Valve Arrangement:OHV
Valve head diameter:INTAKE24.875-25.125 mm (0.9793-0.9892 in)
EXHAUST23.800-24.200 mm (0.9370-0.9527 in)
Stem outer diameter:INTAKE5.474 mm (0.2155 in)
EXHAUST5.464 mm (0.2151 in)
Cam lobe profile:INTAKE27.608 mm (1.0870 in)
EXHAUST27.770 mm (1.0930 in)

Tightening torque specs

Tightening torque specs
Cylinder head (torque in 2 increments) Step 1: 12.0 Nm (1.2 kgf·m; 8.9 lb·ft)
Step 2: 24.0 Nm (2.4 kgf·m; 17.7 lb·ft)
Connecting rod12.5 Nm (1.3 kgf·m; 9.2 lb·ft)
Flywheel74.0 Nm (7.5 kgf·m; 54.6 lb·ft)
Spark plug27.0 Nm (2.75 kg·m; 20.0 ft·lb)

Service Information

Valve clearance
Intake0.0762-0.1270 mm (0.0030-0.0050 in)
Exhaust0.0762-0.1270 mm (0.0030-0.0050 in)
Oil system
Oil typeAPI SJ or higher
Recommended oilSAE 10W-30
Oil capacity0.6 liters (0.63 US.qts, 0.53 Imp. qts)
Ignition system
Spark plugKohler 1413214-S
Spark plug gap0.76 mm (0.0300 in)
Ignition module air gap0.254 mm (0.010 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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