Ignition System - Stihl MS 650 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
No spark
12
Cause
Spark plug boot is loose
Ignition lead loose in ignition
module
Spark plug sooted, smeared
with oil
Too much oil in fuel mix, poor
quality 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 or is missing
Weak magnetization in flywheel –
pole shoes have turned blue
Crankcase damaged (cracks)
Faulty Master Control lever or
ignition module
Remedy
Press boot firmly onto spark plug
and fit new spring if necessary
Secure the ignition lead
Clean the spark plug or replace if
necessary
Fill up with fuel mix of specified
quality
Set air gap correctly
Install new flywheel
Install new flywheel, fit new key
Install new flywheel
Replace crankcase
Check operation of Master Control
lever and ignition module
MS 650, MS 660