51Series 4180 Powerhead
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.
Troubleshooting on the ignition 
system should always begin at the 
spark plug, b 4.3.
The electronic (breakerless) ignition 
system basically consists of an 
ignition module (1) and flywheel (2).
– Remove the shroud, b 5.7
The ignition lead is molded to the 
ignition module.
: Use suitable pliers to pull the leg 
spring out of the spark plug boot.
– Unhook the leg spring from the 
ignition lead.
– Push the spark plug boot back a 
little in the direction of the ignition 
module.
– Cut about 10 mm off the end of 
the ignition lead.
– Coat end of ignition lead with oil.
: Pinch the hook of the leg spring 
into the center of the lead, i.e. 
about 15 mm from the end of the 
lead.
: Pull the lead back into the boot so 
that the leg spring locates 
properly inside it.
Reassemble in the reverse 
sequence.
: Check if spark plug has a 
detachable adapter nut (arrow). If 
so, make sure it is properly fitted 
and firmly tightened.
8. Ignition System 8.1 Spark Plug Boot