seat adjustment JEEP DJ 1953 User Guide

FUEL
SYSTEM

14261

FIG.
E-6—CARBURETOR—
F4 ENGINE,
LATE
MODEL 1—
Choke
Clamp Bracket
2—
Throttle
Lever
and Shaft
3—
Choke
Shaft and
Lever

4—
Bowl
Vent Tube
5—
Fuel
Inlet Elbow
6—
Dash
Pot Bracket 7—
Throttle
Lever
8—
Dash
Pot Plunger
9—
Dash
Pot Assembly
10—
Lock
Nut
11— Stop Pin

1
2—Idle Mixture
Limiter
Cap
13—
Idle
Speed Adjusting Screw 14—
Fast
Idle Connecting Rod
E-11.
Float System

The
float system, Fig. E-7, consists of a float,
float
pin,
air horn gasket and the
needle
and seat assembly. These parts control the fuel level in the

carburetor
bowl, a supply being maintained for all
systems under all operating conditions. To prevent
float
vibration
from affecting the fuel level, the
inlet or float valve is spring loaded. Should the

needle
and seat
become
worn, they must be re­
placed
with a matched set, including the spring,

which
is the only way they are supplied. When
reinstalling
the float, be sure to install the float pin

with
the
stop
shoulder on the side away from the bore of the carburetor.

E-12.
Float Adjustment

Correct
float level setting is required for accurate
metering of fuel in both low- and high-speed jets.

To
set the float, remove and invert the bowl cover. Remove the bowl cover gasket. Allow the weight
of the float to rest on the
needle
and spring. Be

sure
there is no compression of the spring other

than
the weight of the float. Adjust the level by
bending the float arm lip that contacts the
needle
(not the arm) to provide specified clearance be­
tween the float and cover. The specified clearance of the float is
L74\F
[6,74 mm.] on current models
(including
Exhaust
Emission Control) and [7,93 mm.] on early models shown as A in
Fig.
E-8.
FIG.
E-7—FLOAT SYSTEM
1—
Float
and
Lever
Assembly
2—
Needle
Valve and Seat Assembly

3—
Vent

4—
Float
Bowl Cover 5—
Float
7 '.. j
io8Si
i

FIG.
E-8—FLOAT
LEVEL
GAUGING
E-13.
Low-Speed System

Fuel
for idle and early part-throttle operation is
metered through the low-speed system. The low-
speed system is illustrated in Fig.
E-9.
Liquid
fuel enters the idle well through the metering rod jet.

Low-speed
jet measures the amount of fuel for
idle and early part-throttle operation. Air-by-pass,
economizer, and idle air bleed are carefully
cali­

brated
orifices which serve to break up the liquid
fuel
and mix it with air as it
moves
through the passage to the idle port and idle adjustment screw

port.

E-14.
Idle Mixture Adjustment

Note:
The idle mixture adjustment procedure for
the late model
YF-4941S
and
YF-6115S
Carter
Carburetor
equipped with the
External
Idle

Mixture
Limiter
Cap is the same as outlined below 114

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

E

FIG.
E-9—LOW-SPEED
SYSTEM

1—
Body
Flange 6—Idle Air Bleed

2—
-Idle
Adjustment Screw Port
7—Air
By-pass
3—
Idle
Port 8—Economizer

4—
Idle
Well
9—Metering Rod Jet
5—
Low
Speed Jet 10—Idle Adjustment Screw
in
Pars.
"A"
through
"D";
however, because of the

Idle
Limiter
Cap,
the idle mixture screw
CANNOT

be adjusted in the counter-clockwise
(rich)
direc­
tion. The adjustment is made from the
rich
stop

position and the mixture screw is turned in (clock­
wise) approximately %
turn
to
"Lean
Best
Idle."
Refer
to Fig. E-6.

The
"Lean
Best
Idle"
method of idle
setting
is as
follows:

a.
Any scheduled service of ignition system should precede this adjustment.

b.
Connect tachometer or vacuum
gauge
to
engine.

c.
Warm
up
engine
and stabilize temperatures.

d.
Adjust
engine
idle to
speed
desired, using throt­tle idle
speed
adjusting screw.
e. Carburetors without Idle
Limiter
Cap
turn
idle
mixture
screws out (counterclockwise) until a
loss

of
engine
speed
is indicated; then slowly
turn
mix­
ture
screw in (clockwise
-leaner)
until maximum

speed
(RPM) is reached. Continue turning in (clockwise) until
speed
begins
to drop;
turn
mixture
adjustment back out (counterclockwise
-rich)
until
maximum
speed
is just regained at a "lean as
possible" mixture adjustment.

E-15.
High-Speed System

Fuel
for part-throttle and full-throttle operation
is supplied through the high-speed system shown

in
Fig. E-10. A metering rod and metering rod

jet
control the amount of fuel admitted through the nozzle for high-speed operation. The lower
end of the metering rod is calibrated in size to

accurately
meter the fuel required. As the rod
|
13346

FIG.
E-10—HIGH-SPEED
SYSTEM

1—Nozzle 7—Pump Diaphragm
Spring

2
—Metering
Rod 8—Diaphragm Assembly

3—
Pump
Lifter
Link
9—Chamber

4—
Metering
Rod Arm Assembly
10—Metering
Rod Jet 5—
Diaphragm
Shaft
11—Carburetor
Casting

6—
Upper
Pump Spring 12—Carburetor Bore is automatically raised and lowered in the jet,
the opening in the jet is varied in size to supply
fuel
proportionate to the requirements through the
higher
speed
and power range. The metering rod
is both mechanically and vacuum controlled and is
attached to the metering rod arm assembly.
During
part-throttle operation, vacuum in chamber

pulls
diaphragm down, holding metering arm
assembly against pump lifter
link.
Movement of the metering rod is controlled by the
pump lifter
link
which is attached to the carburetor
throttle shaft. At all
times
vacuum in the chamber
is strong
enough
to overcome the tension of pump

diaphragm
spring. Upper pump spring serves as

a
bumper upon deceleration and as a delayed
action spring upon acceleration. Under any operat­ ing condition, when the pump diaphragm spring
overcomes vacuum in the chamber, the metering

rod
will
move
toward the wide throttle (power) position.

Note:
Nozzle is pressed in and should not be
removed.

E-16.
Metering Rod Adjustment

Check
metering rod adjustment each time the

carburetor
is reassembled. Before adjustment is
made, be sure that the flat of metering rod arm
is parallel to the flat of pump lifter
link
as shown
(Fig.
E-10.).
With
the throttle valve
seated
in
car­

buretor
bore, press down on the upper end of
diaphragm
shaft until the diaphragm
bottoms

in
the vacuum chamber. The metering rod should
now
seat
on casting with the metering rod
arm
flat against the pump lifter
link.
If the meter­
ing rod
does
not
seat
on the casting (check by 115

E

FUEL
SYSTEM
pressing downward on metering rod) or
seats
be­
fore the metering rod arm makes flat contact with the pump lifter link, make adjustment by bending
the lip on the metering rod arm.

E-17.
Choke System

The
choke system consists of a manually-operated
choke valve, a fast-idle connecting rod, and a fast-
idle arm. The choke valve is offset-spring loaded to prevent over-choking during the starting warm-
up period. When the choke valve is moved to a closed position for starting, the fast idle connector

rod
in Fig. E-ll revolves the fast idle link.
This
action increases the
engine
idle speed to prevent stalling during the warm-up period. A fast-idle
connector rod return spring prevents partial closing
of the choke valve. pump lifter which is connected to the throttle.

This
movement forces fuel from the chamber
above the diaphragm through discharge pump check valve and discharge pump jet.
This
auxiliary discharge of fuel supplies
engine
requirements for

quick
acceleration and heavy loads. When the
throttle is closed, the diaphragm is again pulled
down by high vacuum and another measured
charge of fuel enters the chamber above the
diaphragm
through the intake passage to be
available for the next cycle of operation.

Note:
The pump jet (see insert drawing in Fig.

E-12)
projecting into the air stream is permanently pressed into the carburetor body and should not
be removed. Also, carburetor design makes it im­ possible to adjust the pump stroke.
FIG.
E-ll—FAST
IDLE
ADJUSTMENT

1—Fast
Idle
Connector Rod
2—Fast
Idle
Link
E-18.
Fast
Idle Adjustment

With
the choke held in wide open position, lip (No. 1) (Fig.
E-ll)
on the fast-idle rod should con­
tact the
boss
on the body casting. Adjust by bend­
ing the fast-idle link at
offset
as shown by (No. 2).

E-19.
Accelerating Pump System

The
accelerating pump system shown in Fig. E-12
provides a measured amount of fuel for rapid acceleration and smooth
engine
operation when
the throttle is opened at lower speeds. In operation,
vacuum
is applied to the underside of diaphragm
at all times when the
engine
is running.
Lower

and
more uniform vacuum is provided by vacuum
restriction
and vacuum bleed passage. When the
diaphragm
is in its maximum down position at
low throttle resulting from high vacuum in chamber the chamber above the diaphragm is full of fuel

which
has been admitted through intake passage.
When
the throttle is opened, vacuum drops in the
chamber and the diaphragm is initially forced
upward
by the spring on the diaphragm shaft.
The
upward motion is picked up by accelerator
|
13347

FIG.
E-12—ACCELERATING
PUMP
SYSTEM

1—
Pump
Fuel
Passage
6—Intake
Passage

2—
Discharge
Pump Jet 7—Diaphragm

3—
Pump
Check
Valve
Ball
8—Vacuum Chamber 4—
Bail
Check
Weight
9—Vacuum
Restriction
Jet

5—
Pump
Lifter
Arm 10—Vacuum Bleed Passage
E-20.
Accelerating Pump Maintenance

If
engine
acceleration is unsatisfactory, remove the
pump diaphragm and check the diaphragm for wear

or
damage. Then remove the pump check retainer
ring
located directly above the pump check weight

and
pump ball check. Pump ball check must seat

properly
as a leak
will
cause poor acceleration performance. Inspect and replace all worn or
damaged parts.
Clean
and blow out all passages

with
compressed air.
Note
that when testing the pump for discharge volume with the carburetor
off the engine, only half of the maximum pump capacity
will
be discharged. When the
engine
is
operating, vacuum controls the balance of dis­ charge. 116

E

FUEL
SYSTEM
Note:
Do not remove pressed-in parts such as
nozzle, pump jet, or antipercolator air bleed.

j.
Remove body flange attaching screws, body flange assembly, and gasket.

k.
Remove idle-adjustment screw, spring, idle

port
rivet, throttle lever assembly, washer, fast
idle arm, throttle plate screws, throttle plate, and throttle shaft.
1. Remove throttle shaft seal by prying out seal

retainer.

Note:
Do not remove pressed-in vacuum passage

orifice.

m.
Remove choke valve screws and choke valve.

Unhook
choke spring and slide shaft from housing,
n.
Wash all parts in carburetor cleaning solution

and
blow out passages with compressed air. Do not immerse diaphragm or seals in cleaning solution.

Inspect
all parts for wear or damage. Always use
new gaskets when reassembling.

E-22.
Carburetor
Reassembly

•
Refer to Fig. E-13.

To
expedite
reassembly, it is advisable to group all

related
parts by the circuit to which they belong.

a.
Install
throttle shaft seal and retainer in flange casting.

b.
Install
fast-idle
arm,
washer, and lever assembly
on throttle shaft. Slide shaft into place and install throttle valve.

c.
Install
idle port rivet plug and idle adjusting

screw
and spring.

d.
Attach flange assembly to body casting. Use new gasket.
e.
Install
low-speed jet assembly.
f.
Early
production models install pump intake
strainer
in pump diaphragm housing and carefully
press into recess.

Note:
If strainer is even slightly damaged, a new
one must be installed.
g.
Install
pump diaphragm assembly in diaphragm housing.
Then,
install pump diaphragm spring
(lower)
and retainer.

h.
Install
pump lifter
link,
metering rod
arm,
upper
pump spring, and retainer.

I.
Install
metering rod jet.

Note:
No gasket is used with this jet.

j.
Install
diaphragm housing attaching screws in
the diaphragm housing, making sure that the

edges
of the diaphragm are not wrinkled.
Lower

into place and tighten screws evenly and securely,
k.
Install
throttle shaft seal, dust seal washer, and
shaft seal spring.

I.
Install
pump connector
link
in the throttle arm
assembly.
Install
throttle shaft arm assembly on
throttle shaft guiding connector
link
in pump lifter

link
hole.
CAUTION:
Linkage
must not bind in any throttle
position. If binding occurs,
loosen
clamp screw in
throttle arm, adjust slightly, then retighten screw.

m.
Install
pump check disc, disc retainer, and lock

ring.

n.
Install
metering rod and pin spring. Connect
metering rod spring.
o.
Check
and if necessary correct meter ing rod adjustment. Follow procedure of
Par.
E-16.
p.
Install
needle
seat and gasket assembly, needle,
float
and
float pin. The
stop
shoulder on the float
pin
must be on the side away from the bore of
the carburetor.

q.
Set float level to specifications. Follow pro­ cedure of
Par.
E-12.

r.
Install
air horn gasket and air horn assembly.

Install
attaching screws, lock washers, and choke
tube clamp assembly. Tighten center screws first,
s. Slide choke shaft and lever assembly into place
and
connect choke lever
spring.
Install
choke valve.
Center
the valve by tapping lightly, then hold in
place with fingers when tightening screws,
t.
Install
fast-idle connector rod with
offset
portion
of rod on top and pin spring on outside.
Install
fast-idle connecting rod spring.

E-23.
Correcting Acceleration
Flat
Spot

Early
production
Carburetor
Models 938-S, 938-
SA,
938-SC

Inasmuch
as a flat
spot
on acceleration or low speed
stumble can
come
from causes other than
car­

buretor
malfunction, it is recommended that
engine

tuning be thoroughly checked before attempting
any
actual carburetor work. Make sure that
ignition, compression, and timing are correct and
that fuel pump is supplying enough gas. Also, the F-head
engine
employs a water-heated intake

manifold.
Proper vaporization of the fuel depends
on correct intake manifold temperature. Since this
temperature is controlled by the cooling system
thermostat, include an operational check of the
thermostat when diagnosing the stumble. Operating
temperatures consistently below
155°F.
can cause stumble.

If
the stumble persists, a
YF-938-S,
YF-938-SA,

or
YF-938-SC
carburetor can be converted to a
YF-938-SD
carburetor by installing Special Kit
924161, consisting of a pump discharge check
needle, a metering rod, and a metering rod jet. If this kit is installed, the pump discharge check

needle
replaces the original
ball,
weight, and re­

tainer
and the small wire-type retainer used with
the
ball
check assembly must not be reinstalled.

When
installing the kit, check the size of the pump discharge jet, No. 2, Fig. E-14.
Early
production
YF-938S
and
YF-938SA
carburetors have a .025" [0,635 mm.] jet installed. If the carburetor being
converted has a .025" jet it must be opened up to .031" [0,787 mm.] by running a No. 68
drill
through
the jet as shown in
Fig.
E-14.
The jet must be drilled
as it is a pressed in part and cannot be replaced.
Upon
completing the installation of the conversion

kit,
mark
or tag the carburetor to indicate that it
is a
YF-938SD.
118

E

FUEL
SYSTEM
There
are six adjustments: curb idle speed, curb
idle mixture, float level, float drop, accelerator pump, and fast idle.
This
carburetor has six basic systems: float, low
speed, main metering, power, accelerator pump

and
choke.

E-26.
Float System

The
float system controls fuel level in the
car­

buretor fuel bowl. It maintains constant fuel level
to assure proper metering through all operating
ranges.

Fuel
enters the carburetor through the inlet screen
and
inlet valve. It flows past the valve
needle
and into the fuel bowl.
Fuel
continues to flow until

increasing
fuel level raises the float to a position
in
which it forces the inlet valve
needle
into its seat.
This
closes
the inlet valve. As fuel is used

from
the bowl, the float
moves
downward slightly.
This
allows the valve
needle
to
move
away from its
seat.
This
again allows fuel to enter the fuel bowl
to maintain fuel level. In this manner, float level maintains fuel level constant. See Fig. E-17. 12838

FIG.
E-17—FLOAT
SYSTEM
1—
Internal
Bowl
Vent
4—Float Tang

2—
Float
5—Float Needle
3— Needle
Pull
Clip
6—Needle
Seat

A
float prong, at the
rear
of the float arm
between

the float hangers, prevents the float from moving too far downward, yet allows it to
move
downward

far
enough to allow maximum fuel flow into the
bowl. A
pull
clip connects the float arm to the valve needle.
This
keeps the
needle
from sticking in the seat because of
dirt
or gum formation.

E-27.
Idle System

During
engine
idle operation, air flow through the

carburetor
venturi is very low. It is insufficient to
cause fuel to flow from the main discharge nozzles.
Therefore,
the idle system supplies fuel-air mixture

during
idle and low-speed operation.

The
idle system consists of the idle tubes, idle pas­

sages,
idle air bleeds, idle mixture adjustment
needles, off-idle discharge
slots
and idle discharge ports. See Fig. E-18.
FIG.
E-18—IDLE
SYSTEM

1—
Idle
Air Bleed 6—Throttle
Valve
2—
Idle
Air Bleed 7—Idle Needle
Hole

3—
Idle
Restriction
8—Adjustment Needles

4—
Lower
Idle
Restriction
9—Main
Metering
Jets
5—
Off
Idle
Discharge Port 10—Idle Tube
A—Throttle
Valve
in Off
Idle
Position
In
idle speed position, each throttle valve is slightly
open.
This
allows a small amount of air to pass

between
the carburetor bore
wall
and the throttle valve. Since there is not enough air flow for ven­

turi
action, manifold vacuum draws fuel directly

from
the fuel bowl through the idle system.

Fuel
from the float bowl passes through each main metering jet into the main well. A metered amount
of fuel flows through the idle tube restriction. It
then passes up the idle tube to a passage where

it
is mixed with air drawn through two calibrated
idle air bleeds.
Fuel-air
mixture then flows through

a
calibrated restriction into a vertical passage. It passes through another calibrated restriction to the off-idle discharge slot just above each throttle
valve.
This
injects additional air. It then flows
through the idle discharge port. The idle mixture
needle
controls the amount of fuel-air mixture

which
enters the carburetor bore at curb-idle posi­ tion of the throttle valve.

As
the throttle valve
opens
farther, more and more of the off-idle discharge slot is
exposed
to manifold
vacuum.
This
slot supplies additional fuel-air mix­
ture to
meet
off-idle
engine
requirements.

E-28.
Main
Metering System

As
the throttle valve continues to open, its
edge
moves
away from the carburetor bore
wall.
This
reduces vacuum applied to the idle discharge port
and
off-idle discharge slot, so that the idle system

ceases
to supply fuel-air mixture.

With
increased throttle opening, air velocity through the venturi increases.
This
causes a de­
crease of pressure in the carburetor bore, which is multiplied in the venturi. See Fig. E-19.
Since
the low air pressure (vacuum) is in the
venturi
at this time, fuel flows as follows:

Fuel
from the float bowl passes through the main metering jets into the main well and rises into the main well tubes. Air enters the main well through the main well air
bleeds
and mixes with 120

E

FUEL
SYSTEM
port into the venturi.

The
check
ball
in the pump plunger head is a vapor
vent for the pump well. Without this vent, vapor
pressure in the pump would force fuel from the
pump system into the
engine
manifold, causing

hard
starting when the
engine
is hot.
There
is another
hole
in the pump lever, into which
the accelerator pump rod can be inserted to pro­ vide quicker pump action.
This
adjustment setting
is used only in extreme cold temperature condi­ tions. The pump discharge check
ball
in the dis­
charge passage prevents discharge of fuel from the
pump nozzles when the accelerator pump is in­
operative.

E-31.
Choke System

The
choke system consists of a manually-operated
choke valve, a fast-idle connecting rod, and a fast-
idle arm. The choke valve is offset-spring loaded
to prevent over-choking during the starting
warm-
up period. When the choke valve is moved to a
closed position for starting, the fast idle connector

rod
revolves the fast idle
link.
This
action increases
the
engine
idle speed to prevent stalling during the

warm-up
period. A fast-idle connector rod return
spring
prevents
partial
closing of the choke valve.

E-32.
Carburetor
Removal

a.
Remove attaching wing nut and air cleaner from
carburetor.

b. Remove throttle cable from
ball
stud on throttle
lever adapter.

c.
Disconnect fuel line from carburetor inlet fitting.

d.
Disconnect positive crankcase ventilator
hose
from
nipple on carburetor body.
e. Disconnect distributor vacuum line from throttle body of carburetor.
f. Remove four attaching cap screws, carburetor,
and
gasket from intake manifold.

E-33.
Air
Horn
Body Removal and Disassembly

a.
Remove attaching screws, and carefully lift air
horn
body upward to remove from fuel bowl body.
b. Place air horn body in inverted position on
bench. Remove float hinge pin and lift float as­ sembly from cover. Remove inlet valve
needle
from
float arm. Remove
needle
seat, fiber gasket

and
seat screen from air horn body; discard gasket. See Fig. E-22.

c.
Depress shaft and allow spring to snap re­ peatedly to remove power piston from air horn body.
This
will
force power piston retaining washer

from
air horn body.

d.
Remove retainer from end of accelerator pump
plunger shaft. Remove pump assembly from pump

inner
arm. Loosen set screw on inner arm and re­

move
outer lever and shaft from plunger. Remove gasket from air horn body or fuel bowl body and

discard.

e. Remove two retaining screws and choke valve plate from choke shaft. Withdraw choke shaft from
air
horn body. Remove choke lever and collar from
choke shaft.
Note
position of choke lever in relation
12856
FIG.
E-22—AIR HORN BODY

1
—
Float

2— Power Piston
3—
Pump
Plunger
4—
Choke
Valve to choke trip lever at end of the choke shaft for

ease
in reassembly.

E-34.
Fuel
Bowl Body Disassembly

a.
Remove return spring of pump plunger and pump well from fuel bowl body. Remove small

aluminum
check
ball
from
bottom
of pump well
by inverting fuel bowl body and shaking into hand. Remove pump inlet screen from
bottom
of fuel bowl.
b. Remove main metering jets from fuel bowl body
using Tool C-3748.

c.
Remove power valve and fiber gasket from fuel bowl body; discard gasket.

d.
Remove three attaching screws, venturi cluster
assembly, and gasket from fuel bowl body. Center
screw has smooth shank and fiber gasket for the accelerator pump fuel bypass and seal.
e. Using a
pair
of long nosed pliers, remove T-
shaped retainer, accelerator pump discharge spring

and
steel discharge
ball
from fuel bowl body.
f. Remove two inserts from main well.

E-35.
Throttle Body Removal and Disassembly

a.
Invert
fuel bowl body; remove three attaching
screws,
throttle body and gasket; discard gasket.
b. Remove idle mixture adjustment
needles
and
springs from throttle body.

Note:
No further disassembly of the throttle body
is required. The throttle valves should never be
removed, as the idle and
spark
holes
are drilled in
direct
relation to the location of the throttle valves

and
shaft. Removal of the throttle valves
will
upset
this alignment. The throttle body assembly is serv­ iced only as a complete assembly with throttle valves intact.

E-36.
Carburetor
Cleaning and Inspection
Dirt,
gum, water, or carbon contamination on the 122

'Jeep9
UNIVERSAL
SERIES
SERVICE
MANUAL

E
exterior moving parts of a carburetor are
often

responsible for unsatisfactory performance.
For
this

reason,
efficient carburetion depends upon careful cleaning and inspection while servicing.

a.
Thoroughly clean carburetor castings and metal
parts
in carburetor cleaning solvent.

Caution:
Accelerator pump plunger and any fiber

or
rubber parts should never be immersed in
car­

buretor
cleaner. Wash pump plunger in cleaning
solvent.

b.
Blow out all passages in the castings with com­
pressed air. Dry all parts with compressed air.

Make
sure all jets and passages are clean. Do
not use wire to clean fuel passages or air bleeds.

c.
Check
inlet valve
needle
and seat for wear. If

wear
is noted, the assembly must be replaced.

d.
Check
float hinge pin for wear and check float
for damage.

e.
Check
throttle and choke shaft bores for wear

and
out-of-round.
f. Inspect idle mixture adjustment
needles
for
burrs
or
grooves; replace if damaged.
g. Inspect cup of accelerator pump plunger; re­
place if damaged, worn, or hardened. Inspect pump

well
in bowl for wear or scoring.

h.
Check
filter screens for
dirt
or lint.
Clean,
and

if
they remain
clogged,
replace.

i.
If for any reason parts have
become
loose
or
damaged in the cluster assembly, the assembly
must be replaced.

Note:
Use ijew gaskets whenever the carburetor
is disassembled.

E-37.
Throttle Body Assembly
a.
Install
idle mixture adjustment
needles
and
springs in throttle body. Tighten finger-tight, then
unthread
one
turn
as a preliminary adjustment
setting.

Caution:
Do not force idle mixture adjustment
needles
against
seats
or damage may result.

b.
Invert
fuel bowl body and place new throttle
body gasket on bowl. Fasten throttle body to bowl
body with three screws and lockwashers; tighten

securely.

E-38.
Fuel
Bowl Body Assembly

a.
Drop steel discharge check
tall
of accelerator
pump into discharge hole.
Install
pump discharge

spring
and T-shaped retainer. Stake retainer in
place.

Note:
Top of retainer must be flush with flat

surface
of fuel bowl body.

b.
Install
two inserts in main well. Align surface
on lip of insert with flat surface in recess on top
of main well.
Install
venturi cluster with gasket,

and
tighten mounting screws evenly and securely.

Be
certain that center screw is fitted with fiber gasket, and that a special smooth shank screw is
used.
c.
Install
two main metering jets, power valve
gasket and power valve.

d.
Install
small aluminum inlet check
ball
in ac­

celerator
pump inlet at
bottom
of pump well. In­

sert
pump return spring into well, and center by
pressing spring downward with finger.

e.
Install
pump inlet screen in
bottom
of fuel

bowl.

E-39.
Air
Horn Body
Assembly

a.
Install
choke lever and collar on choke shaft.

Prong
on choke lever must face away from air

horn
body and be on top of choke trip lever.
b.
Install
choke shaft and lever assembly into the

air
horn. Choke rod
hole
in the choke lever must
face fuel inlet side of carburetor.

c.
Install
choke valve plate in choke shaft so that
letters RP
will
face upward in finished carburetor.
Install
two new valve plate attaching screws, but
do not tighten securely until valve plate is centered.

To
center choke valve plate on choke shaft, hold
choke valve tightly closed, then slide choke shaft

inward
to obtain approximately .020" [0,508 mm.]

clearance
between
choke trip lever and choke lever

and
collar assembly. Tighten choke valve screws

securely,
and stake lightly in place. Choke valve

will
be perfectly free in all positions when installed
correctly.

d.
Insert
outer accelerator pump lever and shaft as­ sembly into air horn body, with lever pointing to­

ward
choke shaft.
Install
inner pump arm, with plunger
hole
inward,
and tighten set screw securely.
Position pump plunger assembly on inner pump
arm,
with pump shaft pointing
inward,
and install

retainer.

e.
Install
needle
seat screen on inlet valve seat. In­

stall
seat and gasket in air horn body. Tighten seat
securely with a wide-blade screwdriver.
f.
Install
power piston into vacuum cavity.
Lightly
stake piston retainer washer in place. Piston should

travel
freely in cavity.
g.
Install
air horn gasket on air horn body, fitting
gasket over guide pin.

h.
Attach inlet valve
needle
to float.
Carefully

position float and insert float hinge pin. Drop tang
at
rear
of float arm downward toward air horn.

i.
Install
fuel inlet fitting, if removed.

j.
With
air horn assembly inverted, measure the distance from the air horn gasket to top of float
at toe \%£f [27,78 mm.] for standard carburetors

and
\%i [29,36 mm.] for exhaust emission control
equipped carburetors, as shown in Fig. E-23. Use
float level
gauge
J-5127-2. Bend float arm as re­

quired
to adjust float level.

k.
With
air horn body held upright, measure dis­
tance from gasket to
bottom
of float
pontoon
at outer end. Use a l7/s" [47,625 mm.] float drop

gauge.
Bend float tang, as required, to adjust float

drop.
See Fig. E-24.

I.
Carefully
place air horn body on fuel bowl
body, making certain that the accelerator pump
plunger is properly positioned in the pump well.
Lower
the cover gently, straight down; install air 123

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

E
is generally caused by excessive
engine
idle speed

in
combination with retarded ignition timing,

engine
heat soak or the use cf low octane fuel.
Should
engine
dieseling
(engine
running after ignition key is turned off) be experienced on V-6

engine
equipped vehicles, installation of Idle Stop
Valve
Kit
Part
No.
991722
will
correct the
difficulty.

E-43.
Fast
Idle Adjustment
No fast idle speed adjustment is required.
Fast

idle is controlled by the curb idle speed adjustment

screw.
If curb idle speed is correctly set and the choke rod is properly adjusted, fast idle speed
will

be correct;

E-44.
Dash Pot Adjustment —
F4
and V-6 Engine

•
Refer to
Figs.
E-27 and E-28. Before adjusting the dash pot, the
engine
idle speed

and
mixture should be correctly adjusted.
With
the

engine
idling at normal operating temperature,
adjust
the dash pot as follows:

The
dash pot adjustment is made with the throttle
set at curb idle (not fast idle). Loosen dash pot lock
nut and
turn
the dash pot assembly until dash pot
plunger contacts the throttle lever without the plunger being depressed.
Then
turn
the dash pot
assembly 2turns against the throttle lever, de­ pressing the dash pot plunger. Tighten the lock nut
securely. As a final check, open carburetor and
allow throttle to snap closed. Time dash pot delay­ ing action from the point where the throttle lever
hits the dash pot to the point where the lever
stops

moving. The dash pot should delay or cushion
closing action for two seconds by saying, "One
thousand and one, one thousand and two."
14204

FIG.
E-27—DASH
POT
ADJUSTMENT—V6
ENGINE
1—
Throttle
Lever
3—Dash Pot
2—
Plunger
4—Lock
Nut
E-45.
FUEL
PUMP
(DOUBLE-ACTION)
—

HURRICANE
F4
ENGINE

•
Early
Models

The
double-action fuel pump consists of a metal
body, a rubber diaphragm, rocker arm, valves,
FIG.
E-28—DASH
POT
ADJUSTMENT—F4
ENGINE

1—
Throttle
Lever
3—Dash Pot
2—
Plunger
4—Lock
Nut springs, gaskets, and a glass sediment bowl complete

with
strainer.
The
metal pump body provides
a
work­
ing housing for the diaphragm, lever, valves, and springs. The fuel pump is mounted on the left side
of the
engine
and is actuated by an eccentric on the
camshaft. An air
dome
is cast into the metal cover
to relieve the carburetor
needle
valve and the fuel
pump diaphragm of excessive pressure when the

carburetor
needle
valve is closed.

Tracing
pump operation from the beginning, the
camshaft eccentric forces the diaphragm up, over­
coming spring pressure.
This
action creates a
partial
vacuum
in the pump chamber.
Fuel
from the main

tank
is forced into the low-pressure pump chamber
through the open disc valve. Incoming fuel supplies
the force necessary to open the valve, which is

a
one-way check valve. As the
engine
camshaft continues to rotate, spring pressure forces the

diaphragm
downward as the pump rocker arm
follows the camshaft eccentric to its low
spot.

The
downward action of the diaphragm
closes

the intake valve and forces fuel to the carburetor

reservoir
through the pump
outlet
valve. Both intake and
outlet
valves are one-way check valves
opened and closed by fuel flow. No mechanical components are required in the control of valve
operation.

Fuel
is delivered to the carburetor only when the float
needle
is off its seat. When the fuel level in the carburetor bowl is high enough for the float to
force the
needle
against its seat, pressure backs up
to the fuel pump air
dome
and causes the diaphragm
to
stop
pumping. In this position, the pump is said
to be balanced because the pressure in the pump- to-carburetor line equals that of the diaphragm

spring.
In this way, fuel from the pump to the
carburetor
is always under pressure. The carburetor

uses
fuel, causing the float to drop and
pull
the

carburetor
needle
valve off its seat. Pressure in the pump immediately drops as fuel is delivered to the

carburetor
reservoir. Almost instantaneously the

diaphragm
again starts operating to pump more 125

G
COOLING SYSTEM
12761

FIG.
G-10—WATER
PUMP—

CROSS-SECTIONAL
VIEW
—
DAUNTLESS
V-6
1—
Hub

2—
—Shaft
and Bearing
3—
Cover

4—
Impeller

5—
Ceramic
Seal
6—
Seal
Assembly front end of the pump body. Position the seal,

washer,
and pump seal on shaft flush against the ground seat in the water pump body. Place the

impeller
on an arbor press and press the long end
of the shaft into the impeller until the end of the shaft is flush with the hub of the impeller. Support
the assembly on the impeller end of the shaft and
press the pulley hub on the shaft until the shaft end is flush with the pulley hub. Move the shaft

in
the pump body to align the retaining wire
grooves
in the bearing and pump body and place
the bearing retaining wire in position.

G-l
5. Water Pump Removal and Replacement — Dauntless V-6 Engine

Drain
the cooling system. Remove the fan belt and remove the cooling fan and pulley from the hub on
the water pump. Disconnect the
hoses
from the
water
pump. Remove the cap screws that secure
the water pump to the timing chain cover; remove
the water pump. Do not disassemble the water

pump;
it is serviceable only as an assembly. When

replacing
the water pump, torque the water pump cap screws 6 to 8 lb-ft. [0,829 a 1,106 kg-m.].

G-16.
Antifreeze Solutions

When
water freezes it expands approximately 9%

in
volume. When water, confined in a cooling sys­
tem, freezes it exerts tremendous pressures causing
serious damage. To prevent freezing, antifreeze can
be added to the water to lower its freezing point.

The
two
types
of antifreeze commonly used today have either a methanol or ethylene glycol base,

and
contain corrosion inhibitors. The only anti­
freeze recommended for the cooling system of

'Jeep'
vehicles is ethylene glycol (permanent type).

Methanol
base antifreeze evaporates with the water
when the vehicle is operated at warmer tempera­
tures and requires more attention to avoid
loss
of
protection. Ethylene glycol base antifreeze seldom
evaporates at normal operating temperatures.

Methanol
solution is injurious to vehicle finishes.
Should
any be spilled on the vehicle, it should be
washed off immediately with a
good
supply of cold water without wiping or rubbing. Under ordi­

nary
conditions, ethylene glycol is not injurious to
vehicle finishes.

Warning.*
Drinking
ethylene glycol antifreeze or its
solutions can be harmful or fatal. Do not use anti­
freeze containers for
food
or beverages.

A
table in Par.
G-2
2
gives
the protection obtained
by the addition of various amounts cf ethylene glycol.
Before installing antifreeze, inspect the cooling sys­
tem to be sure it is clean, leak-proof, and otherwise

in
proper operating condition.
Drain
the cooling system, see Par. G-3. Pour in 3 quarts [3 ltr.] of

clean
water, add the required quantity of anti­ freeze, then add clean water to within 1" [2,54 cm.] of the top of the overflow pipe to allow for expan­
sion when hot. Run the
engine
until it is
warm.

Then
recheck the solution level.
Check
the anti­
freeze protection with a hydrometer reading.

G-l7.
Inhibited Coolant Solutions

All
'Jeep5 vehicles equipped with either the
Hur­
ricane
F4 or Dauntless V-6
engine
should use only

inhibited
year-round, permanent-type
engine
cool­
ant
solutions that are formulated to withstand two

full
calendar years of normal operation without

draining
or adding inhibitors. The
engine
cooling
system should be completely drained and the
rec­
ommended coolant installed every two years. Be-
fo
a
installing the permanent-type solution, inspect the cooling system to be sure it is clean, leakproof,

and
in proper operating condition.

Note:
Water alone, methanol, or alcohol-type anti­
freeze is definitely not recommended for 'Jeep*
Vehicles.

G-l8.
Fan Belt

The
fan, water pump, generator or alternator are
driven
by a V-belt. The drive of the V-belt is on
the side of the V. A fan belt that is too tight
will

cause
rapid
wear of the alternator or generator and
water
pump bearings. If the belt is too
loose,
it may
slip
preventing the water pump from properly cool­
ing the
engine
or the generator or alternator from
properly
charging the electrical
circuit.
Use fan belt
tension
gauge
Tool W-283 to properly adjust belt.

The
fan belt is properly adjusted when it can be
deflected Vi" [13 mm.] with strong thumb pres­

sure
applied midway
between
the fan and alter­

nator
pulleys.
Check
this adjustment and inspect the condition of the fan belt at each
engine
lubri-
168

H

ELECTRICAL
SYSTEM

FIG.
H-42—GROWLER
d.
Install
the armature in starter motor frame,
using care to align the four brushes and brush
springs on the commutator so that they are free to
move
and are square on the commutator.

e.
Install
the thrust washer on the shaft.
Lubricate

the plug and bearing in the end plate.
Install
the
end plate.
Install
the two through
bolts
and tighten securely.

f.
On Prestolite V6 starting motors, check pinion position by measuring from the centerline of the
pinion housing mounting bolt
holes
to the outside

edge
of the pinion.
Correct
measurement with the
Bendix
drive retracted is [19,05 mm.] to
%"
[22,23 mm.]; with drive extended, 1%"

[34,93
mm.] to 1^" [38,10]. Adjust by installing

thrust
washers just inside the commutator end
head or intermediate bearing as required. The
Bendix
drive retaining pin must not project
beyond the outside diameter of the pinion
sleeve.

H-104.
Bench Test

The
motor should first be checked to see that the
free running
voltage
and current are within specifi­ cations. To
test,
connect the motor to a battery,
ammeter and voltmeter. If the current is too high
check
the bearing alignment and end play to make

sure
there is no binding or interference. Using a

spring
scale and torque arm check the stall torque to see that the motor is producing its rated
crank­

ing power. The stall torque
will
be product of the

spring
scale reading and the length of the arm

in
feet.
If the torque is not up to specifications

check
the seating of the brushes on the commutator
and
the internal connection of the motor for high
resistance. The Bendix
Folo-Thru-Drive
should be checked for correct operation. The Bendix pinion
should be checked to see that it shifts when the motor is operated under no load.

H-105.
Bendix Folo-Thru Drive (Prestolite)
The
Bendix
Folo-Thru
Drive is designed to over­

come
premature demeshing of the drive pinion
from
the flywheel ring gear until a predetermined

engine
speed is reached. See Fig. H-43. No repairs or adjustments are possible on this

drive
and a
complete
new unit must be installed

if
trouble develops.

H-106.
Lubrication
of
Folo-Thru Drive
A
periodic cleaning and relubrication of the drive is advisable, the frequency of which
will
depend on
the type of service to which the vehicle is sub­
jected and the locale of operation.

a.
Remove the starting motor from the
engine
and take off the outboard housing. The pinion and

barrel
assembly
will
be in the demeshed position
on the screwshaft. Do not
move
it forward
until
after
that portion of the armature shaft ahead
of the pinion has been cleaned. If accidentally ro­
tated to the outer end of the screwshaft it
will

lock
in that position and cannot be forced back.

b.
Do not disassemble the drive for any reason.

c.
Do not dip or wash the drive in any cleaning solution.

d.
Do not remove the drive from the armature
shaft. Remove
excess
oil, grease or foreign matter
from
the armature shaft by wiping it with a clean cloth.
3
10859
FIG.
H-43—BENDIX
FOLO-THRU DRIVE

Dampen
the cloth with kerosene if necessary. A
light film of
SAE
10 oil may then be applied to the shaft.

e.
Now rotate the pinion and
barrel
assembly to the
fully
extended position, thereby exposing the screw­ shaft triple threads. Use a cloth dampened with
kerosene to wipe them clean. Do not use
gaso­
line
or any
commercial cleaner.
If the dirt is

thick
and gummy, apply the kerosene with a small

brush.
Tilt
the starting motor so that a small
amount
will
run under the control nut. Relubricate

with
a thin film of
SAE
10 oil. Use SAE 5 at ex­ tremely low temperatures.

f.
Reassemble the starting motor to the
engine
with the drive in the extended position.
Carefully
mesh the pinion with the flywheel ring gear before
tightening the starter motor mounting bolts. It may 206