Owner's Manual

ManualsBrandsSTIHL ManualsChainsawsSTIHL MS 251

MS 251, MS 251 C

English

45

Checking the Spark Plug

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 that have caused

fouling of spark plug:

– too much oil in fuel mix,

– dirty air filter,

– unfavorable running conditions, e.g.

operating at part load.

WARNING

To reduce the risk of fire and burn injury,

use only spark plugs authorized by

STIHL. Always press spark plug boot (1)

snugly onto spark plug terminal (2) of the

proper size. (Note: If terminal has

detachable SAE adapter nut, it must be

securely 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.

Installing the spark plug

N Fit spark plug by hand

N Tighten the spark plug and press on

the spark plug boot firmly

N Fit the shroud – see "Shroud"

000BA039 KN

A

1

2

000BA071 KN

2310BA012 KN