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Section l-Trouble Shooting
7
(e)
If the
cause of
the trouble has not
been found,
check
the
fuel pump
pressure, and
repair or
repl
ace
the
fuel pump
or
ca
rburetor.
(f)
If
the
fuel
system
is
operating correctly
a
nd
the
engine still stalls, it may be
due to
the
coil
or con-
denser breaking
down
under
operating
temperature.
Check
and
replace
as
necessary.
(4) ENGINE
CONTINUALLY
MISSES AT IDLE.
When the
engine continually misses on
the
same cylin-
ders, the
fault generally lies
in the ignition
system.
(a) Isolate the miss by pulling
one spark plug cable
at a time from the
plugs. Remove
the plugs, then
clean,
inspect,
and adjust them.
Replace those that
are badly
fouled.
(b)
Check the
spark
plug
wires
for
signs of deteri·
oration
a
nd
replace as necessary.
(c)
Remove the distributor
cap and
rotor, the
n
clea
n
and inspect
the
m. Replace if necessary.
(d)
If
none
of the above correct
the
condition,
check
the
compression to
determine if
compression and
in-
take manifold
passages
are satisfactory.
(5)
ENG INE
MISSES ERRATICALLY AT IDLE.
This may be
caused
by
a combination of things.
Check
the following in
sequence:
(a)
Carburetor
(induding
choke operation),
idle
mixture
setting, and
float
level.
(b)
The ignition
system starting
with the
spark
plugs,
if the carburetor
adjustment does not
eliminate
the trouble. Make necessary repairs.
(c)
The
vacuum
lines for
leaks
at
a
ll lines
and
fittings
if the
miss
is
still
present. Make
any
necessary
repairs.
(d)
Valve
operation and
make
a compression
test
if
the miss
p
ersists.
(6)
ENGINE MISFIRES OR
llESITATES
ON AC·
CELERATION.
This
malfunction
is usually
a com·
bination
of faults
in the ignition
and
fuel
system, but
also
can
b
e ca
used by the
exhaust system.
Perform the
following checks
in the
sequence given
:
(a)
Check
the operation
of the
exhaust
thermostat
valve. If
sticking,
free up or replace
as
necessary.
(b)
Check the
paint on
the intake manifold heat
riser
passage.
If
the
p
ai
nt is not burned
off, the
passage
may
be obstructed and the carburetor
may not
be
vapor-
izing
the
gasoline properly.
(c)
Remove the
spark
plugs,
inspect,
clean
and re-
gap. Check to
verify
tha
t the plugs
are of
the proper
heat
range.
R
eplace any
plugs that are defective.
(d)
Remove the distributor
cap and check the
point
gap,
distributor shaft clearance, condition of cam lobes,
and
points.
Make necessary repairs
or
replaceme
nts.
Check
the high tension
wiring
for
signs of
deterioration,
and replace
if
necessary.
(e) Make a
coil and
condenser
check.
Replace
faulty
units.
(I)
Check
fuel pump
pressure
and
adjust carburetor
float level.
Check
accele
rator pump
action and linkage.
(g)
If
the
problem still
persists,
take compression
readings
and check
the
va lve action. Check
the
va
lv~
spring
rates and assembled
height. Repair
or replace
as
necessary.
(7)
ENGINE
DOES
NOT
DEVELOP
FULL
POWER.
Lack
of
power is usually
caused
by poor
compression.
However,
some preliminary
checks
should
be
made. Make
certain
that
the
throttle opens all
the
way,
that the
choke
remains
open, and
that the
gov-
ernor cut-off operates
properly.
(a)
After preliminary
checks are made, check
the
com
pression. This
should quickly
indicate
whether
the
internal
components are operating properly.
(b)
If the
compression
checks
within
limits,
check
the
ignition
system, including initial timing
and
distrib-
utor operation.
(c) If the
compression, and
ignition
system, are satis-
factory, check
the fuel
system, including carburetion
and
fuel pump
pressure.
(d)
If the problem
still
exists,
a
check of
mechanical
components
must be
made.
Check the valve lash,
lift,
and
timing. Repair
or replace as
necessary.
b. Fuel System.
The
fuel
system
consists
of the fuel tank, fuel
pump,
carburetor,
and
connecting
lines. Dirt
and other
foreign
material are a major
source of
fuel system
problem~
and
all components should
be kept
as
clean
as
possible.
(1)
EXCESSIVE FUEL CONSUMPTION.
Faulty
carburetion is usually
responsib le
for
e
xcessive fuel
consumption.
However,
the
following preliminary
checks
should
be made. Check for fuel leaks
in
the
system,
check choke operation and
adjustment,
and
make
cer-
tain
the
accelerator linkage
is free. Check
to see
if the
brakes are
dragging. Then
adjust
the
carburetor.
(a)
Verify the
complaint
with test
equipment
in-
stalled
in
the vehicle. Show the
customer
how improper
operation
of the vehicle will
affect
fuel
conswnption.
(b)
If test
shows
fuel consumption to be excessive,
remove
the carburetor and
rebuild.
Since
poor carbure-
tion
is
usually
a combination of
internal
malfunctions,
it is usually not
advisable
to try to repair only one
system
in the carburetor. Time will be saved
by
a
com-
plete
carburetor overhaul.
(2)
CARBURETOR
FLOODS.
Make
a
visual
in-
spection of the carburetor
for
lea king
gaskets
or
casting
defects. Tape
the
carburetor
bowl.
If the flooding
stops,
the
needle was held
open
by foreign material. If the
flooding
persists,
follow the
steps below:
(a)
Remove the
air
cleane
r
and check choke
oper-
ation.
(b) Check the float level and the
condition
of the
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