English / USA

Checking the Spark Plug

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 – see "Starting / Stopping the Engine".

:Clean dirty spark plug.

:Check 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.

1

000BA036 TR

To reduce the risk of fire and burn injury, use only spark plugs authorized by STIHL. Always press spark plug boot (2) snugly onto spark plug terminal (1) of the proper size. (Note: If terminal has detachable SAE adapter nut, it must be attached.)

A loose connection between spark plug boot and ignition wire connector in the boot may create arcing that could ignite combustible fumes and cause a fire.

48

MS 270, MS 270 C, MS 280, MS 280 C