SECTION
6-
ELECTRICAL SYSTEMS &
COMPONENTS
BATTERY
IGNITION
SYSTEM
These
engines
use
a
battery
ignition
system,
which
uses
the
electrical
charge
stored
in
the
battery
to
induce
a
high
voltage
in
the
ignition
coil.
This
high
voltage
is
impressed
across
the
spark
plugs
where
it
jumps
the
gaps
producing
the
spark
that
ignites
the
air-fuel
mixture
in
the
cylinders.
The
basic
components
of
the
battery
ignition
sys-
tem
are
the
battery,
ignition
coil, condenser, break-
er
points
and
spark
plugs
as
shown
in
Figure
6-1.
F Primary
Circuit.........,.
Secondary
Circuit
rF
--~--
0
~
~
II
----,,
1
lgnilion
,
:II
Switch ' Battery ·
"~
-~--:-
~
- : i
.
High
Tension Lead 4
11
!Spark,&
I
~
~
Co~~nser
ePiug
w
lgn_ilioJ ["TI',, Breaker
1
1 l
Co1l
: 1
~
Poinls
1
-------''~c_Ground
=
-=-
Figure 6-1.
Schematic
of
a Typical Battery Ignition
System
Ignition System Service
Several
factors
contribute
to
the
overall
perfor-
mance
of
an
ignition
system
-
all
components
must
be
in
good
condition
and
the
spark
must
be
properly
timed.
Hard
starting,
low power
and
erratic
operation
can
often
be
attributed
to
faulty
ignition.
The
following
operational
test
will de-
termine
if
the
ignition
system
actually
is
faulty.
29
Operational Test
WARNING:
Performing
this
test
near
explosive
gases
could result
in
bodily
injury
from explosion. Wipe up spilled gaso-
line
and
cover containers
of
flam-
mable
liquids.
Attach
an
in-line
tester
between
each
spark
plug
lead
and
spark
plug.
Crank
engine
rapidly.
If
a
sharp
spark
jumps
the
tester
gap,
the
trouble
apparently
is
no
tin
the
ignition
coil,
condenser,
or
breaker
points.
A
weak
spark
indicates
ignition
trouble.
When
checking
out
an
ignition
system,
the
com-
ponents
most
commonly
requiring
service
or
ad-
justment
should
be
checked first.
Ignition System Analyzers
To
determine
the
condition
of
components
of
the
ignition
system,
an
ignition
tester
should
be
used.
A wide
variety
of
testers
are
available
from
var-
ious
manufacturers
such
as
Graham,
Merc-0-
Tronic
or
Stevens.
These
units
have
provisions
for
testing
all
functions
of
the
ignition
system.
Always
refer
to
the
analyzer
manufacturer
instruction
manual
for
proper
procedures.
SPARK PLUGS
Engine
misfire
or
generally
poor
operation
is
often
caused
by
spark
plugs
in
poor
condition
or
with
improper
gap
setting.
Clean
area
around
spark
plugs
before
removing
to
prevent
dirt
or
debris
from
falling
into
engine.
Every
100
hours
remove
plugs,
check
condition
and
regap
to
.025".
Bend
outside (or grounded) electrode only,
never
the
center
electrode.
Abrasive
cleaning
machines
should
never
be
used.
Best
results
are
obtained
with
new
plugs.
Always
replace
in
pairs
to
prevent
misfiring.
Use
Cham-
pion
spark
plugs
RBL15Y
or
equivalent.
Torque
to
10-15 ft. lbs. (1.4-2.8 Kgm).
Examine
plugs
as
soon
as
they
have
been
removed
-
the
deposits
on
the
tip
are
an
indiciation
of
the
general
condition
of
rings,
valves,
carburetor,
and
ignition
system.
Normal
and
worn
plugs
are
shown
in
the
accompanying
illustrations.
To Next Page
Need help?
General
