Ignition System; Short Circuit Wire - Stihl MS 311 Service Manual

3.5

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
Engine runs roughly, misfires,
temporary loss of power
12
Cause
Spark plug boot is loose
Spark plug sooted, smeared with oil Clean the spark plug or replace if
Ignition lead loose in ignition
module
Fuel/oil mixture
– too much oil
Incorrect air gap between ignition
module and flywheel
Flywheel cracked or
damaged or pole shoes have
turned blue
Ignition timing out of adjustment,
flywheel warped, machined key in
flywheel sheared
Weak magnetization in flywheel
Irregular spark
Engine housing damaged (cracks)
Remedy
Press boot firmly onto spark plug
and fit new spring if necessary
necessary.
If sooting keeps recurring, check air
filter
Secure ignition lead properly
Use correct mixture of fuel and oil
Set air gap correctly
Install new flywheel
Install new flywheel, check
crankshaft stub for damage and
replace crankshaft if necessary
Install new flywheel
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.
Install new engine housing
MS 311, MS 391