Merc-O-Tronics 98 - SERVICE HINTS; Ignition Failure Checks

SERVICE
HINTS
Ignition
Failures
I.
Engine
Misfires
at
Idle or
High Speed,
Presuming
Carburetion
and
Fuel Are
OKr Check
for:
-
Incorrect
sPark
Plug
gaP
Defective
or
loose
sPark
Plugs
Spark
ptugs
of
incorrect
heat
range
Spark
plug
gaP
set
incorrectlY
Sticking
or
weak
breaker
arm
spring
Incorrect
breaker
Point
gaP
Breaker
points
not sYnchronized
Breaker
points
not
properly
adjusted
Loose wire
in
PrimarY
eircuit
Defective
distributor
rotor
Corroded
or
Pitted
breaker
Points
Cracked
distributor
caP
Leaking
or
broken
high tension
wires
Weak
armature
magnets
Worn
cam
lobes
on
distributor
or
magneto
shalt
Worn
distributor
or
magneto
shaft
bushings
Defective
coil or
condenser
Defective
ignition
switch
Spark
timing
out-of
-
adjustment
U.
Engine
Backfires
Through
Exhaust,
Check
for:
-
Cracked
spark
PIug
Porcelain
Carbon
path
in
distributor
caP
Crossed
sPark
PIug
wires
Air
leak
at intake
defelector
Improper
timing
III.
Engine
Pre-Ignition,
Check
for
Ignition
Causes:
-
Spark
advanced
too
far
Incorrect
type sPark
Plugs
Burned
spark
PIug
electrodes
Incorrect
breaker
setting
IV. Starter
Motor
-
If
There
Is
Excessive
current
Draw,
check
for:
-
Broken,
jammed
starter
drive
Dirty,
gummed armature
Shorted
armature
Grounded
armature
or
field
Resistance
from
engine
Misaligned
starting
motor
Worn
armature
shaft
bearings
Misaligned
armature
shaft
Loose
field
Pole
Pieces
4J