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13
MS 780, MS 880
4.5
Ignition System
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
Cause
Remedy
Engine runs roughly, misfires,
temporary loss of power
Spark plug boot is loose
Press boot firmly onto spark plug
and fit new spring if necessary
Spark plug sooted, smeared with oil Clean the spark plug or replace if
necessary.
If sooting keeps recurring, check air
filter
Ignition lead loose in ignition
module
Secure ignition lead properly
Fuel/oil mixture
– too much oil
Use correct mixture of fuel and oil
Incorrect air gap between ignition
module and flywheel
Set air gap correctly
Flywheel cracked or
damaged or pole shoes have
turned blue
Install new flywheel
Ignition timing wrong, flywheel out
of adjustment, key in flywheel has
sheared off
Fit key if necessary and secure
flywheel properly or install new
flywheel
Weak magnetization in flywheel
Install new flywheel
Irregular spark
Check operation of switch shaft/
contact springs and ignition
module.
Faulty insulation or break in ignition
lead or short circuit wire. Check
ignition lead/ignition module and
replace ignition module if
necessary.
Check operation of spark plug.
Clean the spark plug or replace if
necessary.
Crankcase damaged (cracks)
Install new crankcase