Ignition System - Stihl MS 441 Manual

4.5

Ignition system

Extreme caution must be exercised
when looking for faults and when
carrying out maintenance and repair
work on the ignition system.
The high voltages occurring can
cause serious or fatal accidents!
Condition
Engine runs roughly, misfires,
temporary loss of power
MS 441, MS 441 C
Cause
Spark plug boot is loose
Spark plug sooted, smeared
with oil
Ignition lead is loose in ignition
module
Fuel/oil mixing ratio – contains too
much oil
Incorrect air gap between ignition
module and flywheel
Flywheel cracked or has other
damage or pole shoes have turned
blue
Ignition timing wrong, flywheel out
of adjustment, key in flywheel has
sheared off
Weak magnetization in flywheel –
pole shoes have turned blue
Irregular spark
Crankcase damaged (cracks)
Remedy
Press boot firmly onto spark plug
and fit new spring if necessary
Clean the spark plug or replace
if necessary
Secure ignition lead
Use fuel mixture with correct mixing
ratio
Set correct air gap
Install new flywheel
Install new flywheel
Install new flywheel
Check operation of switches /
contact springs and ignition
module.
Faulty insulation or break in ignition
lead or short circuit wire.
Check ignition lead / ignition module
and replace if necessary.
Check operation of spark plug,
clean spark plug and replace if
necessary.
Replace crankcase
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