Stihl HL 45 Product Instruction Manual - Page 22

English N Carry out the standard setting. N Warm up the engine. N Turn high speed screw (H) slightly clockwise (leaner) - no further than stop. NOTICE After returning from high altitude, reset the carburetor to the standard setting. If the setting is too lean there is a risk of engine damage due to insufficient lubrication and overheating. Catalytic Converter Power tools with a catalytic converter (depending on model) must be run on a 50 : 1 mixture of unleaded gasoline and STIHL two-stroke engine oil or equivalent two-stroke engine oil - see chapter on "Fuel". The catayltic converter integrated in the muffler reduces the harmful emissions in the exhaust gas. The correct carburetor setting (if adjustable) and strict observance of the prescribed mix ratio of gasoline and twostroke engine oil are essential to minimize harmful emissions and ensure a long catalytic converter service life. Checking the Spark Plug A Wrong fuel mix (too much engine oil in the gasoline), a dirty air filter and unfavorable running conditions (mostly at part throttle etc.) affect the condition of the spark plug. These factors cause deposits to form on the insulator nose which may result in trouble in operation. If engine is down on power, difficult to start or runs poorly at idling speed, first check the spark plug. N Remove spark plug - see "Starting / Stopping the Engine". N Clean dirty spark plug. N Check electrode gap (A) and readjust if necessary - see "Specifications". N Use only resistor type spark plugs of the approved range. Rectify problems which have caused fouling of spark plug: N Too much oil in fuel mix. N Dirty air filter. N Unfavorable running conditions, e.g. operating at part load. 000BA039 KN 20 HL 45