Ignition System - Stihl FS 240 Service Manual

3.5

Ignition system

Problem
Engine runs roughly, misfires,
temporary loss of power
FS 240 C, FS 260 C, FS 360 C, FS 410 C, FS 460 C-M
Cause
Spark plug boot is loose
Spark plug sooted, smeared with oil Clean the spark plug or replace if
Fuel/oil mixture
– contains too much oil
Incorrect air gap between ignition
module/control unit and flywheel
Flywheel cracked
or has other damage or pole shoes
have turned blue
Incorrect ignition timing, flywheel
out of adjustment
– Key in flywheel has sheared off
Weak magnetization in flywheel
Irregular spark
Remedy
Press boot firmly onto spark plug
and fit new spring if necessary
necessary
In the event of repeated sooting,
check air filter
Use a fuel mixture with the correct
mixing ratio
Set the correct air gap
Install new flywheel
Install new flywheel
Install new flywheel
Check proper functioning of lever
for stop function/contact spring or
slide control/microswitch and
ignition module.
Damaged insulation or interruption
in ignition lead or short circuit wire.
Check ignition lead/ignition module,
replace ignition module if
necessary. Check operation of
spark plug, clean spark plug and
replace if necessary.
Versions with M-Tronic, carry out
diagnosis
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