Advertisement
PART 10-4 MOTORCRAFT MODEL 2100 CARBURETTOR
10-39
A
satisfactory
idle
should
be
obtainable within the range of the idle
adjusting limiters, if all other engine
systems
are
operating
within
specifications.
At pre-delivery, follow the Normal
Idle Fuel Settings for both Engine Off
and
Engine
On and
in
Step 1 of Additional
Idle Speed and Fuel Mixture Procedures.
Other fuel system adjustments should not
be required
at
pre-delivery
service.
Following are the normal procedures
necessary to properly adjust the engine
idle
speed
and fuel mixture. The specific
operations should be followed in the
sequence given whenever the idle speed or
idle full adjustments are made.
In isolated
cases,
a
satisfactory
idle
condition
may
not
be achieved
by
performing' the normal procedures. If this
occurs,
refer
to Additional Idle Speed
and
Fuel
Mixture Procedures.
NORMAL IDLE FUEL
SETTINGS
-
ENGINE OFF
1.
Set the
idle
fuel mixture screw(s)
and
limiter
cap(s)
to
the
full-counterclockwise
position
of
the
limiter
cap(s).
2. Back
off the
curb
idle
speed
adjusting screw (Fig. 10) until the throttle
plate(s) seat in the throttle bore(s}.
3.
Be
sure the dashpot or
solenoid
throttle positioner (if so equipped) is not
interfering with the throttle lever (Fig. 11).
It
may be necessary to loosen the
dashpot or
solenoid
to allow the throttle
plate(s) to seat in the throttle
bore(s).
4. Turn the idle
speed
adjusting
screw inward until it just makes contact
with the screw
stop
on the thottle shaft
and lever assembly. Then, turn the screw
inward
I
1/2 turns to establish a
preliminary idle speed adjustment (Fig. I 0).
5.
Set the
parking brake
while
making
idle
mixture
and
speed
adjustments.
LIMITER STOPS
83114-A
FIG. 9- Motorcraft Modei21DO-D 2-V Idle
Fuel Mixture Adjusting Limiters
Stops-Bottom
NORMAL IDLE FUEL
SETTINGS - ENGINE ON
1. The
engine
and
underhood
temperatures must be stabilized before
idle adjustments are made. Run the engine
a
minimum of 20 minutes at 1500rpm.
This can be done by pos1t10mng the fast
idle
screw or cam follower on the kick-
down step of the fast idle cam (Fig. 12).
2. Check the initial ignition timing
and the di;tributor advance. Use an
accurate-reading tachometer and timing
light when checking the initial ignition
timing and idle fuel mixture and speed.
3.
On vehicles with a manual-shift
transmission, the idle setting must be
made only when the transmission is in
Neutral.
On
vehicles
with
an
automatic
transmisSion, the idle setting is made with
the transmission selector lever in the Drive
range.
FIG.
10- Curb Idle Speed Adjusting Screw
4.
Be sure the choke plate is in the
full-open position.
5.
Turn the headlights on high beam
to place the alternator under a load
condition
in order to properly adjust to
the
specified
engine idle speed.
6.
The final idle speed adjustment is
made
with
the
air
conditioner
(if
equipped) turned ON.
7.
Adjust the engine curb idle rpm
to specifications. The tachometer reading
(rpm) must be taken with the air cleaner
installed. On vehicles with less than 50
miles,
~et
the idle speed approximately 25
rpm below specifications to allow for an
rpm increase as the engine loosens up in
the first 100 miles of driving.
If it is not possible to adjust the idle
speed with the air cleaner installed;
remove it, make the adjustment, then
replace the air cleaner and check again for
the specified rpm.
Manual transmission vehicles may be
fitted with a solenoid throttle positioner.
However this is not connected on these
engines and must be adjusted so as not to
affect the engine idle speed. Idle speed
adjustment is to be made on the normal
throttle stop screw.
8. Turn the idle mixture adjusting
screw(s) inward an equal amount to obtain
the smoothest idle possible within the
OASHPOT
LOCKNUT
83134
-
A
FIG.tt- Dashpot
-
Typical Installation
range of the idle limiter(s}.
Check for idle smoothness only
with
the air cleaner installed.
ADDITIONAL IDLE SPEED
AND FUEL MIXTURE
PROCEDURES
If
satisfactory
idle
condition is
not
obtained after performing the preceding
normal idle fuel
settings, additional checks
of engine systems must be performed.
1. The following items
should be
checked and, if required,
corrected.
a.
Vacuum leaks
b.
Ignition system wiring
continuity
c.
Spark plugs
d.
Distributor breaker point dwell
angle
e.
Distributor point
condition
f.
Initial ignition timing
In certain instances, it may be possible
that the idle condition is not
as
good as
normally
expected.
It
is
suggested
that
the
customer with a new vehicle be
advised
that the vehicle be driven 50 to
I
00 miles.
Then, when the
engine
friction has been
reduced, the idle
condition should be
improved.
If, after the
break-in period, the
idle
condition
is
believed
to
be
unsatisfactory, re-adjust the
engine idle
speed to
specification and observe for a
satisfactory idle.
2.
If the
idle
condition is not
improved after
the items
in
Step 1 have
been checked, perform
the following
engine mechanical
checks:
a.
Fuel Level
b.
Crankcase
ventilation system
c.
Valve
clearance
(using
the
collapsed tappet method
for
hydraulic
valves)
d.
Engine compression
3.
After verification
of all engine
systems has been made.
there
may be
isolated cases where
a satisfactory
idle
condition has not been obtained, due
possibly to a lean idle fuel mixture. If this
condition is encountered, refer
to the
following
operation REMOVAL AND
INSTALLATION OF IDLE LIMITER
CAPS.
Advertisement
