Idle Fuel Mixture And Idle Speed Adjustments; Anti-Stall Dashpot; Initial Idle Speed And Mixture Settings; Hot Idle Rpm Adjustment - Lincoln Continental 1964 Shop Manual

10-18
cient to push fuel out of the nozzles.
Fuel flow from the transition holes
tapers off as the fuel is discharged
through the secondary nozzles.
When the primary throttle plates
begin to close on deceleration, the
secondary plates close mechanically.
The auxiliary secondary throttle
plates are closed by counterweights,
located on the ends of the shaft.
GROUP
10-FUEL SYSTEM
ANTI-STALL DASHPOT
An internal hydraulic anti-stall
dashpot is incorporated in the car-
buretor (Fig. 15) to slow the closing
of the throttle plates to idle position.
When the throttle is opened, the
anti-stall dashpot plunger spring
pushes the plunger upward. The in-
take ball check valve opens, allow-
EJ
IN-CAR ADJUSTMENTS AND REPAIRS
All carburetor adjustments except
the float adjustments, the bench fast
idle speed adjustment and the sec-
ondary throttle lever adjustment can
be made with the carburetor mounted
on the engine. Refer to Part 10-1,
Section 1, for "Carter Carburetor
Bench Adjustments."
IDLE FUEL MIXTURE AND
IDLE SPEED ADJUSTMENTS
The idle fuel mixture is controlled
by the idle mixture adjusting screws
(Fig. 16). Turn the screws inward to
lean the mixture, and outward to
enrich the mixture supplied to the
intake manifold.
The idle. speed (air) adjustment
screw (Fig. 16) is used to adjust idle
speed. Turn the screw outward to
increase speed. Conversely, turn the
screw inward to decrease speed.
Turning the screw outward leans
the mixture, thus requiring an adjust-
ment at the idle mixture screws.
If
one of the idle adjustments is
changed, the other idle adjustments
may also be affected. It is necessary
that the adjustments be made in the
order listed, and all of the idle ad-
justments that follow the one being
made must be checked:
1. Idle Mixture Adjustment.
2. Hot Idle rpm Adjustment.
3. Fast Idle rpm Adjustment.
When setting the engine idle speed
on vehicles equipped with an air con-
ditioner, the air conditioner should
be turned off and the air cleaner re-
moved. If the . air conditioner is
turned on (with the air cleaner
removed), a slight roughness of the
engine idle may be noted. This
may be disregarded, since the air
cleaner traps vapor and allows
them to enrich the mixture to
again regain a smooth idle.
ACCELERATING PUMP STROKE ADJUSTMENT
FAST IDLE SPEED
FIG.
16-ldle Fuel Mixture, Idle Speed and Accelerator
Pump Stroke Adiustment
81968-A
(222) .
ing fuel above the plunger to fill
the cylinder below the plunger. When
the throttle is closed, the plunger is
pushed downward. The intake ball
check valve is closed and fuel below
the plunger is forced through a small
restriction, delaying the downward
movement of the plunger and clos-
ing of the throttle plates.
INITIAL IDLE SPEED AND
MIXTURE SETTINGS
1. Make an initial idle fuel mix-
ture adjustment, if necessary, by
turning both screws inward until
they · lightly touch their seat; then,
back them outward 1 V2 to 2V2 turns.
2. Make an initial idle air mixture
adjustment, if necessary, by turning
the idle air mixture screw inward
until it lightly touches its seat, then
turn it open 3 V2 turns.
HOT IDLE RPM ADJUSTMENT
1. Run the engine until it reaches
normal operating temperature. If
the engine is cold, it should be run
for approximately one-half hour at
1200 rpm to stabilize the tempera-
ture.
2. Allow the throttle to drop back
to the normal idle speed position.
Attach a tachometer to the engine.
Remove the vacuum line from the
vacuum power unit of the automatic
vacuum release parking brake as-
sembly and plug the vacuum line.
Set the parking brake. It is neces-
sary to inactivate the vacuum
power unit to keep the parking
brake engaged during the adjust-
ment procedures.
3. Place a small weight on the idle
compensator spring to hold the com-
pensator closed.
If
the compensator
is open, because of high underhood
temperatures, the idle speed ad-
justment would be incorrect when
the compensator closes.
4. Adjust the idle speed and mix-
ture screws (Fig. 16) to obtain the
specified engine idle speed with the
transmission selector in DRIVE posi-
tion. The final mixture setting
should be slightly on the rich side.
5. Remove the weight from the
compensator spring.
FAST IDLE RPM ADJUSTMENT
This adjustment is made only after
the engine has been run for thirty
minutes at 1200 rpm.