PART
1-1
-
ENGINES
Al
35
8-1
FIG.
9-Cooli"9 S
yslem
EJ
ENGINE TROUBLE
DIAGNOSIS
Engine performance compl
ai
nts
usua
ll
y fall under onc
of
the bas
ic
he
adi
ng
s li s
ted
in
the
"Engine
Trouble Diagnosis Guide," When a
particular trouble
can
not be traced
to
a definite cause by a simple check,
the poss
ib
le items that could be
at
fault are
li
sted in the order of their
probab
le
occurrence, Therefore,
in
most cases, the items should be
checked
in
the order
li
sted.
For
ex-
ampl
e,
under Poor Acceleration, the
ENGINE TROUBLE
DIAGNOSIS
GUIDE
ENGINE
WILL
NOT
CRANK
ENGINE
CRANKS
NORMALLY
, BUT
WILL
NOT
START
The
cause of this trouble
is
usually
in the starting system (Part
10·2).
If
the starting system
is
n
ot
at fault,
check for a hydrostatic lock
or
a
seized engine as follows:
Remove the spa
rk
plu
gs
, then at-
tempt to crank the engine with the
Check
th
e
fu
el supply.
If
there
is
su
ffi
cient fuel in the tank, the cause
of
the trouble probably
li
es
in either
the ignition
Or the fuel system.
To
determine which system is at
fault, perform the following test:
Disconnect a spa
rk
plug wire.
Check the spark intensity
at
the end
of
the
wi
re by installing a terminal
adapter in the terminal of the wire to
be checked.
Ho
ld the adapter ap-
proximately
o/t
o inch from the exhaust
manifold and crank the engine.
IF
THERE
IS
NO
SPARK
OR
A
WEAK
SPARK
AT
THE
SPARK
PLUGS:
The
cause of the
tr
ouble
is
in the
ignition system.
To
determine if the cause
of
the
trouble is in the primary
or
the sec-
ondary
circuit, remove the coil high
1-5
As
the coolant enters the block. it
travels through cored passages to cool
the entire length
of
each cylinder wall.
Upon reaching the rear
of
the cylin-
der
block, the
coo
l
ant
is
directed up-
ward into the cylinder head where it
cools
the
c
ombustion
chambers,
valves, and valve seats on its return
to the front
of
the engine.
At
this point, the
coo
l
ant
flows into
the cool
ant
out
let connection, past
the thermostat
if it
is
open, and into
the top
of
the radiator.
If
the thermo-
stat
is
closed, a small portion
of
the
coo
lant
is
returned
to th
e
water
pump
for recirculation.
The
entire system
is
pre
ss
urized to 13-1 5 psi.
ignition
sy
stem is
li
sted as a probable
cause
of
the trouble. All the ignition
system items that affect acceleration
are listed.
The
se items should all be
checked before proceeding to the next
probable cause.
starter.
If
the engine cranks. it indi-
cates that water is
le
aking into the
cylinders. Remove the cylinder head
and inspect the gasket and/
or
head
for cracks. Examine the cy
li
nder
block for cracks.
tension lead from the top of the
dis-
tributor and hold it a
ppro
ximately
~o
inch fr
om
the cylinder head. With the
ignition on,
crank
the engine and
check for a spark.
If
the s
park
at the coil high tension
lead is good, the cause
of
the trouble
is probably in the distributor
cap
or
rotor.
If
there is no
spark
or
a weak spark
at the coil high tensi
on
lead, the
cause
of
the trouble
is
probably in
the primary circuit, coil to distribut
or
high tension lead, or the coil.
IF
THERE
IS A
GOOD
SPARK
AT
THE
SPARK
PLUGS:
Check the spa
rk
plugs.
If
the spark
plugs
are
not at fault, check the
following items:
CHOKE
Check the choke linkage for bind-
ing
or
damage. Make certain the
CONTINUED
ON
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