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Kohler K181 Engine

General Technical Data

Kohler K181 Engine Specifications

Engine Model ............... Kohler K181 (K181T)
Engine Type ............... Air-cooled 4-stroke single cylinder gasoline
Number of Cylinders ............... 1
Displacement, L (cu in) ............... 0.308 (18.6)
Engine Bore, mm (in) ............... 74.6 (2.94)
Engine Stroke, mm (in) ............... 69.9 (2.75)
Maximum Horse Power, hp (kW) ............... 8.0 (6.0)
Rated Engine Speed, rpm ............... 3600
Fuel System ............... Carburetor
Carburetor Model ............... Kohler/Walbro
Carburetor Type ............... Fixed main jet or adjustable main jet
Lubrication System ............... Splash type
Cooling System ............... Forced-air
Ignition System ............... Magneto or battery
Starter Type ............... Retractable (K181T) or electric

Kohler K181 Maintenance Data

Engine Oil Type (Summer Time) ............... SAE 30W
Engine Oil Type (Winter Time) ............... SAE 5W-20, 5W-30
Oil Classification ............... API SF or SG
Oil Capacity, L (qts) ............... 1.2 (1.3)
Plug Type ............... Champion RJ8C
Plug Gap, mm (in) ............... 0.65 (0.0256)
Intake Valve Clearance, mm (in) ............... 0.15-0.20 (0.0059-0.0079)
Exhaust Valve Clearance, mm (in) ............... 0.43-0.48 (0.0169-0.0189)

Service Intervals

Change Engine Oil ............... Every 25 hours
Clean Air Cleaner Paper Element ............... Every 100 hours
Check Spark Plug ............... Every 100 hours
Replace Fuel Filter ............... As required
Check and Adjust Valve Clearance ............... Every 500 hours

Kohler Carburetor Tune-Up

Low Idle ............... 1-1/4 turns
High Idle ............... 2 turns

Walbro Carburetor Tune-Up

Low Idle ............... 1-1/2 turns
High Idle ............... 3/4 turns

Kohler K181 Service Data

Cylinder Block

Sleeve Internal Diameter, mm (in) ............... 74.6252-74.5998 (2.938-2.937)
Piston Skirt Outer Diameter, mm (in) ............... 74.4143-74.3737 (2.9297-2.9281)
Top Compression Ring End Gap, mm (in) ............... 0.177-0.432 (0.007-0.017)
Second Compression Ring End Gap, mm (in) ............... 0.177-0.432 (0.007-0.017)
Connecting Rod Small End Inside Diameter, mm (in) ............... 15.8877-15.8953 (0.6255-0.6258)
Piston Pin Outside Diameter, mm (in) ............... 15.8673-15.8724 (0.6247-0.6249)

Cylinder Head

Intake Valve Head Diameter, mm (in) ............... 34.925 (1.375)
Exhaust Valve Head Diameter, mm (in) ............... 28.575 (1.125)
Stem Outside Diameter (Intake, Std), mm (in) ............... 7.886-7.899 (0.3105-0.311)
Stem Outside Diameter (Exhaust, Std), mm (in) ............... 7.848-7.861 (0.309-0.3095)
Valve Guide Inside Diameter (Intake, Exhaust), mm (in) ............... 7.894-7.919 (0.312-0.313)
Valve Seat Angle (Intake, Exhaust), degrees ............... 89
Valve Seat Width (Intake), mm (in) ............... 0.936-1.139 (0.037-0.045)
Valve Seat Width (Exhaust), mm (in) ............... 0.936-1.139 (0.037-0.045)
Valve Guide Depth (Intake, Exhaust), mm (in) ............... 33.194 (1.312)
Valve Face Angle (Intake, Exhaust), degrees ............... 45

Crankshaft

Crankpin Diameter, mm (in) ............... 30.01 (1.186)
Crankshaft Main Bearing Journal Diameter, mm (in) ............... 29.88 (1.181)
Crankshaft Oil Seal Journal Diameter (Front), mm (in) ............... 28.46 (1.125)
Crankshaft Oil Seal Journal Diameter (Rear), mm (in) ............... 28.46 (1.125)

Kohler K181 Tightening Torque Specifications

Cylinder Head Bolts, Nm (ft-lbs) ............... 20-27 (15-20)
Flywheel, Nm (ft-lbs) ............... 115-122 (85-90)
Spark Plug, Nm (ft-lbs) ............... 25-30 (18-22)
Connecting Rod, Nm (ft-lbs) ............... 22.5 (16.7)
Governor Bushing, Nm (ft-lbs) ............... 14.6-16.9 (10.8-12.5)
Fuel Pump Mounting Screws, Nm (ft-lbs) ............... 4.2-5.1 (3.1-3.8)