Ignition System - Stihl MS 460 Service Manual

4.4

Ignition System

Warning!
Exercise extreme caution while
carrying out maintenance and repair
work on the ignition system. The
high voltages which occur can
cause serious or fatal accidents!
Condition
Engine runs roughly, misfires,
temporary loss of power
MS 460, MS 460 C
Cause
Spark plug boot is loose
Spark plug sooted, smeared
with oil
No ignition spark
Incorrect air gap between ignition
coil and flywheel
Flywheel cracked or has other
damage or pole shoes have turned
blue
Crankcase damaged (cracks)
Check operation of spark plug.
Inspect Master Control lever,
ignition coil/lead for damage
insulation and leakage current.
No ignition spark
Ignition timing wrong, flywheel out
of adjustment, key in flywheel has
sheared off
Weak magnetization in flywheel –
pole shoes have turned blue
Remedy
Press boot firmly onto spark plug
and fit new spring if necessary
Clean the spark plug or replace if
necessary
Faulty insulation on ignition lead or
short circuit wire. Use ohmmeter to
check ignition lead for break. If
break is detected or high resistance
measured, fit a new ignition lead
Set air gap correctly
Install new flywheel
Replace crankcase
Clean or replace spark plug,
replace faulty parts of ignition
system
Check operation of Master Control
lever and ignition module
Install new flywheel
Install new flywheel
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