Stihl 4180 Series Service Manual

Series 4180 Powerhead 5
3.3 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, tem-
porary loss of power
Spark plug boot is loose Press boot firmly onto spark plug, check
leg spring, replace if necessary
Spark plug sooted, smeared with oil Clean the spark plug or replace if
necessary
Wrong electrode gap Check electrode gap, adjust if necessary
Incorrect air gap between ignition module
and flywheel
Set air gap correctly
Flywheel cracked or has other damage,
pole shoes have turned blue
Replace flywheel
Ignition timing incorrect: Flywheel out of
adjustment, flywheel key sheared
Replace flywheel
Weak magnetization in flywheel pole
shoes
Replace flywheel
Intermittent or weak ignition spark Check operation of switch / contact springs
/ ignition module (with ZAT 3 or ZAT 4),
replace if necessary
Clean the spark plug or replace if
necessary

Stihl 4180 Series Specifications

General

Brand	Stihl
Model	4180 Series
Category	Engine
Language	English