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Checking the Spark Plug
Cutting tool rotates when engine is idling
:Turn idle speed screw (LA) slowly counterclockwise until cutting tool
stops rotating and then turn the screw about another 1/2 to 1turn in the same direction.
Erratic idling behavior, engine stops even though setting of LA screw is correct, poor acceleration
Idle setting too lean:
:Turn low speed screw (L) counterclockwise (about 1/4 turn) until the engine runs and accelerates smoothly.
Erratic idling behavior
Idle setting too rich:
:Turn low speed screw (L) clockwise (about 1/4 turn) until the engine runs and accelerates smoothly.
000BA002 KN
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.
:Remove spark plug as described in chapter "Starting / Stopping the Engine".
:Clean dirty spark plug.
:Check the electrode gap (A) and readjust if necessary – see "Specifications".
:Use only resistor type spark plugs of the approved range.
Rectify problems which have caused fouling of spark plug:
:Too much oil in fuel mix.
:Dirty air filter.
:Unfavorable running conditions, e.g. operating at part load.
Fit a new spark plug after approx. 100 operating hours
or earlier if the electrodes are badly eroded.
40 | FS 120, FS 120 R, FS 200, FS 200 R, FS 250, FS 250 R |