IGNITION SYSTEM
32
Spark Plug Service
1. Check spark plu
with the chart in this subsection
and replace followin
the specifications
iven on
this pa
e.
CAUTION: Do not clean plu
with a sand blaster.
2. Clean with a wire brush removin
the carbon
buildup. Check conditions of the plu
for crackin
or dama
e. Replace as necessary.
CD Pack Operation
The Capacitive Dischar
e (CD) system (see Fi
ure 47)
is breakerless and contains electronic components that
replace mechanical points and related accessories
(such as a breaker cam, spark advance assembly,
etc.).
Figure 47
3297-015
As the flywheel ma
net passes the CD Pack, an AC
volta
e is induced into the char
e coil. This AC volta
e
is converted by a rectifier into a DC si
nal, which is
then stored in a capacitor. (See Fi
ure 48.)
Figure 48
3297-016
When the SCR is tri
ered or “fires”, up to 200 volts
DC, stored in the capacitor, travels to the spark coil.
Here it is stepped up to as much as 25,000 volts and is
dischar
ed across the electrodes of the spark plu
.
(See Fi
ure 49.)
I
nition timin
(when the SCR fires) is also determined
by the flywheel key and the keyways in the flywheel
and crankshaft. Dama
e to any of these parts will
affect the i
nition timin
.
Figure 49
3297-017
Item Specification/Action
Plu
type NGK BPMR4A or
equivalent
Frequency of chan
e As needed
Check, clean, and
ap Every 50 hours
Gap See specifications
Torque value See specifications
A. CD I
nition Module
To Next Page
Loading...
