CH260-CH440 Service Manual - Kohler Engines

Electrical SystemSPARK PLUGSCAUTIONElectrical Shock can cause injury.Do not touch wires while engine is running.Spark Plug Component and DetailsInspectionInspect each spark plug as it is removed from cylinderhead. Deposits on tip are an indication of generalcondition of piston rings, valves, and carburetor.Normal and fouled plugs are shown in following photos:NormalABPlug taken from an engine operating under normalconditions will have light tan or gray colored deposits. Ifcenter electrode is not worn, plug can be set to propergap and reused.WornCDA Wire Gauge B Spark PlugC Ground Electrode D GapNOTE: Do not clean spark plug in a machine usingabrasive grit. Some grit could remain in sparkplug and enter engine causing extensive wearand damage.Engine misfire or starting problems are often causedby a spark plug that has improper gap or is in poorcondition.Engine is equipped with following spark plugs:Gap 0.76 mm (0.03 in.)Thread Size 14 mmReach 19.1 mm (3/4 in.)Hex Size 15.9 mm (5/8 in.)Refer to Maintenance for Repairs/Service Parts.ServiceClean out spark plug recess. Remove plug and replace.1. Check gap using wire feeler gauge. Adjust gap to0.76 mm (0.03 in.).2. Install plug into cylinder head.3. Torque plug to 27 N·m (20 ft. lb.).On a worn plug, center electrode will be rounded andgap will be greater than specified gap. Replace a wornspark plug immediately.Wet FouledA wet plug is caused by excess fuel or oil in combustionchamber. Excess fuel could be caused by a restricted aircleaner, a carburetor problem, or operating engine withtoo much choke. Oil in combustion chamber is usuallycaused by a restricted air cleaner, a breather problem,worn piston rings, or valve guides.32KohlerEngines.com17 690 01 Rev. E