Kohler Command PRO CH26

General Technical Data

Kohler CH26 Engine Specifications

Engine Model ..................... Kohler Command PRO CH26 EFI
Engine Type ..................... 4-cycle OHV V-Twin cylinder air-cooled gasoline
Number of Cylinders ..................... 2
Displacement, cc (cu.in) ..................... 725 (44.0)
Cylinder Bore, mm (in) ..................... 83.0 (3.27)
Piston Stroke, mm (in) ..................... 67.0 (2.64)
Rated Engine Power, hp (kW) ..................... 26.0 (19.4)
Rated Engine Speed, rpm ..................... 3600
Peak Torque, Nm (ft-lbs) ..................... 54.2 (40.1)
Torque Speed, rpm ..................... 2800
Low Idle Speed, rpm ..................... 1500
High Idle Speed, rpm ..................... 4200
Compression Ratio ..................... 9.0:1
Fuel System ..................... Electronic fuel injection (EFI)
Lubrication System ..................... Full pressure
Oil Filter Type ..................... Full-flow
Air Cleaner Type ..................... Replaceable, paper element
Oil Capacity, L (qts) ..................... 1.9 (2.0)
Electrical System Rating, Volts ..................... 12
Starter Type ..................... Electric

Dimensions and Weight

Overall Length, mm (in) ..................... 355 (14.1)
Overall Width, mm (in) ..................... 451 (17.7)
Overall Height, mm (in) ..................... 483 (19.0)
Dry Weight, kg (lbs) ..................... 43.0 (94.0)

Kohler CH26 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 Filter), L (qts) ..................... 1.9 (2.0)

Ignition System

Spark Plug Type ..................... Champion RC12YC
Spark Plug Gap, mm (in) ..................... 0.76 (0.030)
Module Air Gap, mm (in) ..................... 0.28-0.33 (0.011-0.013)
Speed Sensor Air Gap, mm (in) ..................... 1.50±0.25 (0.059±0.010)
Thread Size, mm (in) ..................... 14 (0.55)
Reach, mm (in) ..................... 19.1 (0.75)
Spark Plug Torque, Nm (ft-lbs) ..................... 27 (20)

Service Intervals

Replace Air Cleaner (Low-Profile) ..................... Every 100 hours
Change Engine Oil ..................... Every 100 hours
Clean Oil Cooler Fins ..................... Every 100 hours
Check Air Filter (Heavy-Duty) ..................... Every 150 hours
Change Oil Filter ..................... Every 200 hours
Replace Fuel Filter ..................... Every 200 hours
Replace Spark Plug ..................... Every 200 hours
Replace Prymary Air Filter (Heavy-Duty) ..................... Every 300 hours
Replace Secondary Air Filter (Heavy-Duty) ..................... Every 600 hours

Kohler CH26 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)
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)
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)

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
Valve Seat Angle (Intake/Exhaust), degrees ..................... 89
Intake Valve Insert Outside Diameter, mm (in) ..................... 36.987-37.013 (1.4562-1.4572)
Exhaust Valve Insert Outside Diameter, mm (in) ..................... 32.987-33.013 (1.2987-1.2997)
Intake Valve Guide Depth, mm (in) ..................... 4.00 (0.1575)
Exhaust Valve Guide Depth, mm (in) ..................... 6.50 (0.2559)
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 Surface 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) ..................... 0.025-0.048 (0.0010-0.0019)
Middle Compression Ring Groove Clearance, mm (in) ..................... 0.015-0.037 (0.0006-0.0015)
Oil Control Ring Groove Clearance, mm (in) ..................... 0.026-0.176 (0.0010-0.0070)
Top Compression Ring End Gap, mm (in) ..................... 0.25-0.56 (0.0100-0.0224)
Middle Compression Ring End Gap, mm (in) ..................... 0.25-0.56 (0.0100-0.0224)
Piston Thrust Face Outside Diameter (Std), mm (in) ..................... 82.986 (3.2671)
Piston Thrust Face Outside Diameter (Wear Limit), mm (in) ..................... 82.841 (3.2614)
Piston Thrust Face to Cylinder Bore Clearance, mm (in) ..................... 0.001-0.045 (0.039-0.0018)

Tightening Torque Specs

Cylinder Head Nut ..................... 16.9-33.9 Nm (12.5-25.1 ft-lbs)
Cylinder Head Bolt ..................... 22.6-41.8 Nm (16.7-30.8 ft-lbs)
Rocker Arm Screw ..................... 11.3 Nm (8.3 ft-lbs)
Connecting Rod Cap ..................... 22.6 Nm (16.7 ft-lbs)
Flywheel Retaining Screw ..................... 66.4 Nm (49.1 ft-lbs)
Intake Manifold Mounting ..................... 7.4-9.9 Nm (5.5-7.3 ft-lbs)
Speed Control Bracket ..................... 7.3-10.7 Nm (5.4-7.9 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)
Fuel Pump Screw ..................... 2.3 Nm (1.7 ft-lbs)
Spark Plug ..................... 27 Nm (20.1 ft-lbs)