Kohler Command PRO CH742

General Technical Data

Kohler CH742 Engine Specifications

Engine Model ..................... Kohler Command PRO CH742
Engine Type ..................... 4-cycle V-Twin cylinder air-cooled gasoline
Number of Cylinders ..................... 2
Displacement, cc (cu.in) ..................... 747 (46.0)
Cylinder Bore, mm (in) ..................... 83.0 (3.27)
Piston Stroke, mm (in) ..................... 69.0 (2.70)
Maximum Engine Power, hp (kW) ..................... 25.0 (18.6)
Maximum Engine Speed, rpm ..................... 3600
Peak Torque, Nm (ft-lbs) ..................... 55.9 (41.2)
Torque Speed, rpm ..................... 2400
Compression Ratio ..................... 9.1:1
Lubrication System ..................... Full pressure
Oil Filter Type ..................... Full-flow
Air Cleaner ..................... Replaceable, paper element
Oil Capacity, L (qts) ..................... 1.9 (2.0)
Electrical System Rating, Volts ..................... 12
Starter Type ..................... Electric

Fuel System

Fuel System Type ..................... Carburetor
Carburetor Model ..................... Keihin
Carburetor Type ..................... Two-Barrel, fixed main jet
Fuel Pump Type ..................... Pulse or Mechanical
Fuel Filter Type ..................... In-line
Governor Type ..................... Mechanical

Dimensions and Weight

Overall Length, mm (in) ..................... 371 (14.6)
Overall Width, mm (in) ..................... 451 (17.7)
Overall Height, mm (in) ..................... 622 (24.5)
Dry Weight, kg (lbs) ..................... 48.0 (105.0)

Kohler CH742 Maintenance Data

Engine Oil

Engine Oil Type (Summer Time) ..................... SAE 10W-30
Engine Oil Type (Winter Time) ..................... SAE 5W-30
Oil Classification (API Service) ..................... SJ or higher
Oil Capacity (w/o Filter), L (qts) ..................... 1.7 (1.8)
Oil Capacity (with New Filter), L (qts) ..................... 1.9 (2.0)

Carburetor Adjustment

Main Fuel ..................... Not adjustable
Idle Fuel ..................... Not adjustable
Float Setting, mm (in) ..................... 1.6±0.5 (0.063±0.02)
Low Idle Speed, rpm ..................... 1200±75
High Idle Speed, rpm ..................... 3600±50

Ignition System

Spark Plug Type ..................... Champion RC12YC
Spark Plug Gap, mm (in) ..................... 0.76 (0.030)
Module Air Gap, mm (in) ..................... 0.20-0.31 (0.008-0.012)
Thread Size, mm (in) ..................... 14 (0.55)
Reach, mm (in) ..................... 19.1 (0.75)
Spark Plug Torque, Nm (ft-lbs) ..................... 27 (20)

Service Intervals

Check Air Cleaner Element ..................... Every 25 hours
Change Engine Oil ..................... Every 100 hours
Clean Oil Cooler Fins ..................... Every 100 hours
Change Oil Filter ..................... Every 200 hours
Replace Fuel Filter ..................... Every 200 hours
Check Carburetor Adjustment ..................... Every 200 hours
Replace Air Cleaner Element ..................... Every 250 hours
Check and Adjust Valve Clearance ..................... Every 500 hours
Replace Spark Plug ..................... Every 500 hours

Kohler CH742 Service Specifications

Cylinder Block

Cylinder Bore Inside Diameter (Standard), mm (in) ..................... 82.988-83.013 (3.2672-3.2682)
Cylinder Bore Inside Diameter (Wear Limit), mm (in) ..................... 83.051 (3.2697)
Cylinder Bore (Max Out of Round), mm (in) ..................... 0.12 (0.0047)
Cylinder Bore Max Taper, mm (in) ..................... 0.05 (0.0020)
Crankshaft End Play (Free), mm (in) ..................... 0.070-0.590 (0.0028-0.0230)
Crankshaft Bore (Crankcase), mm (in) ..................... 40.965-41.003 (1.6128-1.6143)
Crankshaft Bore (Closure Plate), mm (in) ..................... 40.987-40.974 (1.6136-1.6131)
Crankshaft Bore to Crankshaft Clearance, mm (in) ..................... 0.039-0.074 (0.0015-0.0029)
Crankshaft Bearing Journal Outside Diameter (Flywheel), mm (in) ............. 40.913-40.935 (1.6107-1.6116)
Crankshaft Bearing Journal Max Taper (Flywheel), mm (in) ..................... 0.022 (0.0009)
Crankshaft Bearing Journal Outside Diameter (Closure Plate), mm (in) ....... 40.913-40.935 (1.6107-1.6116)
Crankshaft Bearing Journal Max Taper (Closure Plate), mm (in) ..................... 0.022 (0.0009)
Crankshaft T.I.R (PTO End, Crank in Engine), mm (in) ..................... 0.279 (0.0110)
Crankshaft T.I.R (Entire Crank, in V-Blocks), mm (in) ..................... 0.10 (0.0039)
Connecting Rod to Crankpin Clearance, mm (in) ..................... 0.030-0.055 (0.0012-0.0022)
Connecting Rod to Crankpin Side Clearance, mm (in) ..................... 0.26-0.63 (0.0102-0.0248)
Connecting Rod to Piston Pin Clearance, mm (in) ..................... 0.015-0.028 (0.0006-0.0011)
Connecting Rod Journal Outside Diameter, mm (in) ..................... 35.955-35.973 (1.4156-1.4163)
Connecting Rod Journal Max Taper, mm (in) ..................... 0.018 (0.0007)

Cylinder Head and Valves

Cylinder Head Max Out of Flatness, mm (in) ..................... 0.076 (0.003)
Hydraulic Valve Lifter to Crankcase Clearance, mm (in) ..................... 0.0241-0.0501 (0.0009-0.0020)
Intake Valve Stem to Valve Guide Clearance, mm (in) ..................... 0.038-0.076 (0.0015-0.0030)
Exhaust Valve Stem to Valve Guide Clearance, mm (in) ..................... 0.050-0.088 (0.0020-0.0035)
Intake Valve Guide Inside Diameter, mm (in) ..................... 7.038-7.058 (0.2771-0.2779)
Exhaust Valve Guide Inside Diameter, mm (in) ..................... 7.038-7.058 (0.2771-0.2779)
Valve Guide Reamer Size (Standard), mm (in) ..................... 7.048 (0.2775)
Valve Guide Reamer Size (0.25 Oversize), mm (in) ..................... 7.298 (0.2873)
Intake Valve Minimum Lift, mm (in) ..................... 8.07 (0.3177)
Exhaust Valve Minimum Lift, mm (in) ..................... 8.07 (0.3177)
Nominal Valve Face Angle, degrees ..................... 45
Nominal Valve Seat Angle, degrees ..................... 89
Intake Valve Head Diameter, mm (in) ..................... 33.37-33.63 (1.3138-1.3240)
Exhaust Valve Head Diameter, mm (in) ..................... 29.37-29.63 (1.1563-1.1665)
Intake Valve Stem Diameter, mm (in) ..................... 6.982-7.000 (0.2749-0.2756)
Exhaust Valve Stem Diameter, mm (in) ..................... 6.970-6.988 (0.2744-0.2751)
Camshaft End Play, mm (in) ..................... 0.076-0.127 (0.0030-0.0050)
Camshaft Clearance, mm (in) ..................... 0.025-0.063 (0.0010-0.0025)
Camshaft Bore Inside Diameter, mm (in) ..................... 20.000-20.025 (0.7874-0.7884)
Camshaft Bearing Outside Diameter, mm (in) ..................... 19.962-19.975 (0.7859-0.7864)

Piston and Piston Rings

Piston to Piston Pin Clearance, mm (in) ..................... 0.006-0.017 (0.0002-0.0007)
Piston Pin Bore Inside Diameter, mm (in) ..................... 17.006-17.012 (0.6695-0.6698)
Piston Pin Outside Diameter, mm (in) ..................... 16.995-17.000 (0.6691-0.6693)
Top Compression Ring Groove Clearance, mm (in) ..................... 0.030-0.070 (0.0010-0.0026)
Middle Compression Ring Groove Clearance, mm (in) ..................... 0.030-0.070 (0.0010-0.0026)
Oil Control Ring Groove Clearance, mm (in) ..................... 0.060-0.190 (0.0022-0.0073)
Top Compression Ring End Gap, mm (in) ..................... 0.189-0.277 (0.0074-0.0109)
Middle Compression Ring End Gap, mm (in) ..................... 1.519-1.797 (0.0598-0.0708)
Piston Thrust Face Outside Diameter (Std), mm (in) ..................... 82.978 (3.2668)
Piston Thrust Face Outside Diameter (Wear Limit), mm (in) ..................... 82.833 (3.2611)
Piston Thrust Face to Cylinder Bore Clearance, mm (in) ..................... 0.019-0.062 (0.0007-0.0024)

Tightening Torque Specs

Cylinder Head Nut ..................... 16.9-35.5 Nm (12.5-26.5 ft-lbs)
Cylinder Head Bolt ..................... 22.6-41.8 Nm (16.7-30.8 ft-lbs)
Rocker Arm Screw ..................... 13.6 Nm (10 ft-lbs)
Connecting Rod Cap ..................... 13.6 Nm (10 ft-lbs)
Flywheel Retaining Screw ..................... 66.4 Nm (49.1 ft-lbs)
Intake Manifold Mounting ..................... 7.4 Nm (5.5 ft-lbs)
Carburetor Mounting Nut ..................... 6.2-7.3 Nm (4.6-5.4 ft-lbs)
Closure Plate ..................... 24.4 Nm (18.1 ft-lbs)
Oil Drain Plug ..................... 13.6 Nm (10.1 ft-lbs)
Governor Lever Nut ..................... 6.8 Nm (5.1 ft-lbs)
Ignition Module ..................... 4.0-6.2 Nm (2.9-4.6 ft-lbs)
Muffler Retaining Nut ..................... 24.4 Nm (18.1 ft-lbs)
Oil Pump Screw ..................... 10.7 Nm (7.9 ft-lbs)
Spark Plug ..................... 27 Nm (20.1 ft-lbs)