Kohler Command CV491S

General Technical Data

Kohler CV491S Engine Specifications

Engine Model ..................... Kohler Command CV491S
Engine Type ..................... Gasoline, vertical shaft, four-cycle
Number of Cylinder ..................... Single
Piston Displacement, cc (cu.in) ..................... 490 (29.9)
Engine Bore, mm (in) ..................... 90.0 (3.60)
Engine Stroke, mm (in) ..................... 77.0 (3.03)
Engine Power, Hp (kW) ..................... 17.2 (12.8)
Maximum Torque, Nm (ft-lb) ..................... 37.9 (28.1)
Fast Idle Speed, rpm ..................... 2400
Low Idle Speed, rpm ..................... 1400
Compression Ratio ..................... 8.5:1
Cooling System ..................... Air Intake
Electrical System Rating, Volts ..................... 12
Ignition System Type ..................... Electronic with Spark Advance
Recommended Battery ..................... 12V-250CCA

Fuel System

Fuel System Type ..................... Carburetor
Carburetor Type ..................... Float Fixed Main Jet
Carburetor Model ..................... Walbro or Nikki
Fuel Pump ..................... Diaphragm Type Mechanical Pump
Fuel Filter ..................... In-line
Governor Type ..................... Centrifugal Mechanical Flyweight
Air Cleaner ..................... Replaceable paper element

Lubrication System

Lubrication System Type ..................... Full-Pressure
Oil Pump Type ..................... Gerotor
Oil Filter ..................... Full-flow
Oil Capacity, L (qt) ..................... 1.9 (2.0)

Dimensions

Length, mm (in) ..................... 465 (18.2)
Width, mm (in) ..................... 375 (14.8)
Height, mm (in) ..................... 320 (12.7)
Dry weight, kg (lbs) ..................... 42 (90)

Kohler CV491S Maintenance Data

Cylinder Block and Valves

Cylinder Bore I.D. (Maximum), mm (in) ..................... 90.025 mm (3.5443 in.)
Cylinder Head (Max. Out-of-Flatness), mm (in) ..................... 0.076 (0.003)
Intake Valve Clearance (Cold), mm (in) ..................... 0.038-0.076 (0.0015-0.0030)
Exhaust Valve Clearance (Cold), mm (in) ..................... 0.050-0.088 (0.0020-0.0035)

Ignition System

Spark Plug ..................... Champion RC12YC
Spark Plug Thread Size, mm (in) ..................... 14 (0.55)
Spark Plug Reach, mm (in) ..................... 19.1 (0.75)
Spark Plug Gap, mm (in) ..................... 1.02 (0.040)
Ignition Module Air Gap, mm (in) ..................... 0.200-0.300 (0.008-0.012)
Spark Plug Torque, Nm ..................... 24.4-29.8

Engine Oil

Engine Oil Type (Summer) ..................... SAE 10W-30
Engine Oil Type (Winter) ..................... SAE 5W-20, 5W-30
Oil Classification ..................... SG, SH, 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 Adjustments

Main Fuel ..................... 2-1/2 turns
Idle Fuel ..................... 3/4 to 1 full turn
Low Idle Speed, rpm ..................... 1200±75
High Idle Speed, rpm ..................... 3600±50

Service Intervals

Service Precleaner Element ..................... Every 25 hours
Replace Air Cleaner Element ..................... Every 100 hours
Change Engine Oil ..................... Every 100 hours
Check Carburetor Adjustment ..................... Every 100 hours
Check Spark Plug Condition and Gap ..................... Every 200 hours
Change Oil Filter ..................... Every 200 hours
Replace Spark Plug ..................... Every 300 hours
Check and Adjust Valve Clearance ..................... Every 300 hours

Kohler CV491S Service Specifications

Cylinder Block

Cylinder Bore Inside Diameter (Std) ..................... 90.000-90.025 mm (3.5433-3.5443 in)
Cylinder Bore Inside Diameter (Maximum Wear Limit) ..................... 90.063 mm (3.5458 in)
Cylinder Bore Inside Diameter (Max. Out-of-Round) ..................... 0.12 mm (0.0047 in)
Cylinder Bore Inside Diameter (Max. Taper) ..................... 0.05 mm (0.0020 in)
Rocker Arm Inside Diameter (Std) ..................... 15.837-16.127 mm (0.63-0.64 in)
Rocker Arm Inside Diameter (Maximum Wear Limit) ..................... 16.13 mm (0.640 in)
Rocker Shaft Outside Diameter (Std) ..................... 15.90-15.85 mm (0.63 in)
Rocker Shaft Outside Diameter (Maximum Wear Limit) ..................... 15.727 mm (0.619 in)

Cylinder Head and Valves

Cylinder Head (Max. Out-of-Flatness) ..................... 0.076 mm (0.003 in)
Hydraulic Valve Lifter to Crankcase Running Clearance .............. 0.0124-0.0501 mm (0.0005-0.0020 in)
Intake Valve Stem-to-Valve Guide Running Clearance .................. 0.038-0.076 mm (0.0015-0.0030 in)
Exhaust Valve Stem-to-Valve Guide Running Clearance ............. 0.050-0.088 mm (0.0020-0.0035 in)
Intake Valve Guide Inside Diameter (Std) ..................... 7.038-7.058 mm (0.2771-0.2779 in)
Intake Valve Guide Inside Diameter (Maximum Wear Limit) ..................... 7.134 mm (0.2809 in)
Exhaust Valve Guide Inside Diameter (Std) ..................... 7.038-7.058 mm (0.2771-0.2779 in)
Exhaust Valve Guide Inside Diameter (Maximum Wear Limit) ..................... 7.159 mm (0.2819 in)
Valve Guide Reamer Size (Std) ..................... 7.048 mm (0.2775 in)
Valve Guide Reamer Size (0.25 mm Oversize) ..................... 7.298 mm (0.2873 in)
Intake Valve Minimum Lift ..................... 8.96 mm (0.353 in)
Exhaust Valve Minimum Lift ..................... 9.14 mm (0.360 in)
Nominal Valve Seat Angle ..................... 45 deg

Piston and Piston Rings

Piston to Piston Pin (selective fit) ..................... 0.006-0.017 mm (0.0002-0.0007 in)
Piston Pin Bore Inside Diameter (Std) ..................... 19.006-19.012 mm (0.7483-0.7485 in)
Piston Pin Bore Inside Diameter (Maximum Wear Limit) ..................... 19.025 mm (0.7490 in)
Piston Pin Outside Diameter (Std) ..................... 18.995-19.000 mm (0.7478-0.7480 in)
Piston Pin Outside Diameter (Maximum Wear Limit) ..................... 18.994 mm (0.74779 in)
Top Compression Ring to Groove Side Clearance ..................... 0.060-0.105 mm (0.0023-0.0041 in)
Middle Compression Ring to Groove Side Clearance ..................... 0.040-0.085 mm (0.0015-0.0033 in)
Oil Control Ring to Groove Side Clearance ..................... 0.036-0.186 mm (0.0014-0.0073 in)
Top Compression Ring End Gap Bore ..................... 0.28-0.51 mm (0.011-0.020 in)
Center Compression Ring End Gap Bore ..................... 0.22-0.48 mm (0.008-0.018 in)
Oil Control Ring End Gap ..................... 0.250-0.760 mm (0.0098-0.0299 in)
Piston Thrust Face Outside Diameter (Std) ..................... 89.951-89.969 mm (3.5413-3.5420 in)
Piston Thrust Face Outside Diameter (Maximum Wear Limit) ..................... 89.824 mm (3.5363 in)
Piston Thrust Face to Cylinder Bore Running Clearance ................. 0.031-0.043 mm (0.0012-0.0016 in)

Crankshaft

Crankshaft End Play (free) ..................... 0.0575-0.4925 mm (0.0022-0.0193 in)
Crankshaft End Play (thrust bearing with shims) ..................... 0.050-0.530 mm (0.0020-0.0209 in)
Crankshaft Bore in Crankcase Inside Diameter (Std) ................. 44.965-44.990 mm (1.7702-1.7712 in)
Crankshaft Bore in Crankcase (Maximum Wear Limit) ............... 44.9758-45.0012 mm (1.7707-1.7717 in)
Crankshaft Bore in Crankcase Running Clearance (Std) .............. 0.0300-0.0770 mm (0.0011-0.0030 in)
Crankshaft Bore in Oil Pan Inside Diameter (Std) ..................... 41.965-42.003 mm (1.6521-1.6536 in)
Crankshaft Bore in Oil Pan Inside Diameter (Max Wear Limit) ....... 41.9760-42.0141 mm (1.6526-1.6541 in)
Crankshaft Bore in Oil Pan Running Clearance (Std) .................. 0.0300-0.0880 mm (0.0011-0.0034 in)
Flywheel End Main Bearing Journal Outside Diameter (Std) .......... 44.913-44.935 mm (1.7682-1.7691 in)
Flywheel End Main Bearing Journal Outside Diameter (Max Wear Limit) ............. 44.84 mm (1.765 in)
Flywheel End Main Bearing Journal (Max. Taper) ..................... 0.022 mm (0.0009 in)
Flywheel End Main Bearing Journal (Max. Out-of-Round) ..................... 0.025 mm (0.0010 in)
Oil Pan End Main Bearing Journal Outside Diameter (Std) ...... 41.915-41.935 mm (1.6502-1.6510 in)
Oil Pan End Main Bearing Journal Outside Diameter (Max Wear Limit) ................. 41.86 mm (1.648 in)
Oil Pan End Main Bearing Journal (Max. Taper) ..................... 0.020 mm (0.0008 in)
Oil Pan End Main Bearing Journal (Max. Out-of-Round) ..................... 0.025 mm (0.0010 in)
Connecting Rod Journal Outside Diameter (Std) ..................... 38.958-30.970 mm (1.5338-1.5343 in)
Connecting Rod Journal Outside Diameter (Maximum Wear Limit) ..................... 38.94 mm (1.5328 in)
Connecting Rod Journal (Max. Taper) ..................... 0.012 mm (0.0005 in)
Connecting Rod Journal (Max. Out-of-Round) ..................... 0.025 mm (0.0010 in)
Crankshaft PTO End, Crank in Engine ..................... 0.30 mm (0.012 in)
Crankshaft Entire Crank, in V-Blocks ..................... 0.10 mm (0.0039 in)

Camshaft

Camshaft End Play (free) ..................... 0.088-0.393 mm (0.003-0.015 in)
Camshaft End Play End Play (with shims) ..................... 0.076-0.127 mm (0.003-0.005 in)
Camshaft Running Clearance ..................... 0.025-0.105 mm (0.0010-0.0041 in)
Camshaft Bore Inside Diameter (Std) ..................... 20.000-20.025 mm (0.7874-0.7884 in)
Camshaft Bore Inside Diameter (Maximum Wear Limit) ..................... 20.038 mm (0.7889 in)
Camshaft Bearing Surface Outside Diameter (Std) ..................... 19.962-19.975 mm (0.7859-0.7864 in)
Camshaft Bearing Surface Outside Diameter (Maximum Wear Limit) ................. 19.959 mm (0.7858 in)

Connecting Rod

Connecting Rod to Crankpin Running Clearance (Std) ..................... 0.030-0.055 mm (0.0012-0.0022 in)
Connecting Rod to Crankpin Running Clearance (Maximum Wear Limit) .................. 0.07 mm (0.0025 in)
Connecting Rod to Crankpin Side Clearance ..................... 0.18-0.41 mm (0.007-0.016 in)
Connecting Rod to Piston Pin Running Clearance ..................... 0.015-0.028 mm (0.0006-0.0011 in)
Piston Pin End Inside Diameter (Std) ..................... 19.015-19.023 mm (0.7486-0.7489 in)
Piston Pin End Inside Diameter (Maximum Wear Limit) ..................... 19.036 mm (0.7495 in)

Kohler CV491S Tightening Torque Specs

Cylinder Head, Nm (ft-lbs) ..................... 20.0-40.7 (14.8-30.1)
Rocker Pedestal, Nm (ft-lbs) ..................... 11.3 (8.3)
Rocker Arm Screw, Nm (ft-lbs) ..................... 11.3 (8.4)
Rocker Arm Pivot Stud Torque, Nm (ft-lbs) ..................... 11.3 (8.4)
Connecting Rod Bolt, Nm (ft-lbs) ..................... 11.3-22.7 (8.4-16.7)
Flywheel Retaining Screw, Nm (ft-lbs) ..................... 66.4 (49.1)
Fuel Bowl Retaining Screw, Nm (ft-lbs) ..................... 5.1-6.2 (3.8-4.6)
Valve Cover, Nm (ft-lbs) ..................... 10.7 (7.9)
Starter Mounting Screw, Nm (ft-lbs) ..................... 15.3 (11.3)
Fan, Nm (ft-lbs) ..................... 9.9 (7.3)
Fuel Pump, Nm (ft-lbs) ..................... 9.0 (6.7)
Spark Plug, Nm (ft-lbs) ..................... 24.4-29.8 (18-22)
Ignition Module, Nm (ft-lbs) ..................... 6.2 (4.6)
Muffler Retaining Nuts, Nm (ft-lbs) ..................... 24.4 (18.0)
Oil Filter, Nm (ft-lbs) ..................... 10.4-12.7 (7.5-9.2)
Oil Pan, Nm (ft-lbs) ..................... 24.4 (18.0)
Oil Pump Cover, Nm (ft-lbs) ..................... 6.2 (4.6)
Governor Control Lever, Nm (ft-lbs) ..................... 9.9 (7.3)