fuel type JEEP CJ 1953 Service Manual

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

13330

FIG.
B-4—ENGINE
LUBRICATION
SYSTEM
—
DAUNTLESS
V-6
ENGINE

1—
Rocker
Arm Shaft
2—
Main
Oil
Line

3—
Oil
Inlet where it is connected by a drilled passage in the

cylinder
crankcase to an oil screen housing and
pipe assembly. The screen is submerged in the oil supply and has ample area for all operating condi­
tions. If the screen should
become
clogged
for any reason, oil may be drawn into the system over the
top
edge
of the screen, which is held clear of the

sheet
metal screen housing.

Oil
is drawn into the pump through the screen and
pipe assembly and a drilled passage in the
crank­

case, which connects to drilled passages in the
timing chain cover. All oil is discharged from the
pump to the oil pump cover assembly. The cover
assembly consists of an oil pressure relief valve,
an
oil filter bypass valve and a nipple for installa­
tion of an oil filter. The spring loaded oil pressure

relief
valve limits the oil pressure to a maximum
of 30 pounds [13.607 kg.] per square inch. The

oil
filter bypass valve
opens
when the filter has
become
clogged
to the
extent
that
4V2
to 5 pounds [2.04 a 2.27 kg.] pressure difference exists
between

the filter inlet and exhaust to bypass the oil filter
and
channel unfiltered oil directly to the main oil galleries of the engine.

A
full flow oil filter is externally mounted to the

oil
filter cover nipple on the right side of the en­ gine, just below the alternator. Normally, all
engine

oil
passes through the filter element; however, if
the element
becomes
restricted, a spring loaded bypass valve
opens
as mentioned above. The main

oil
galleries run the full length of the crankcase
and
cut into the valve lifter guide
holes
to supply

oil
at full pressure to the lifters. Connecting pas­
sages
drilled in the crankcase permit delivery of

oil
at full pressure to all crankshaft and camshaft
bearings.
Holes drilled in the crankshaft
carry
oil from the
crankshaft
bearings to the connecting rod bearings.
Pistons and cylinder walls are lubricated by oil
forced through a small notch in the bearing parting
surface on the connecting rod, which registers with
the
hole
in the crankpin
once
in every revolution. Piston pins are lubricated by splash.

Drilled
holes
in the camshaft connect the front camshaft bearing
journal
to the key slot in the front
of the camshaft. Oil flows from the
journal
into
the keyslot over the woodruff key in the space

between
the key and the camshaft sprocket and fuel pump eccentric.

The
forward end of the fuel pump eccentric in­ corporates a relief which allows the oil to escape

between
the fuel pump eccentric and the camshaft

distributor
gear. The oil stream strikes the distri­
butor shaft gear
once
each camshaft revolution, and provides ample lubrication of the timing chain and
sprockets by splash.

The
rocker arms and valves on each cylinder head

are
supplied with oil from the oil galleries through

holes
drilled in the front of the cylinder block and

cylinder
head. The
hole
drilled in the cylinder
head ends beneath the front rocker
arm
shaft brack­ et. A notch cast in the base of the rocker arm shaft

bracket
allows the oil to flow up inside the bracket

in
the space
between
the bracket and bolt, to the
hollow rocker arm shaft which is plugged at both
ends.
Each
rocker arm receives oil through a
hole

in
the underside of the shaft. Grooves in the rocker

arm
provide lubrication of the bearing surface. Oil
is metered to the push rod seat and valve stem
through
holes
drilled in the rocker arm. Excess
oil
drains off and returns to the oil pan through
passages in the cylinder head and block. Refer to
the
Lubrication
Chart
for lubrication frequency and

lubrication
type and grade.

B-7.
Chassis
Lubrication

Chassis
and
engine
should be serviced at periodic
intervals.
Most chassis lubricating points, whether
long-life or conventional, have standard lubrication
fittings. Refer to the
Lubrication
Specifications and

Service
Maintenance Schedule for specific points

and
lubricating time intervals. It is not necessary
to disassemble prepacked joints to lubricate them.

Merely
add new lubricant, as described in Par.
B-3,
to remove all old lubricant.

At
the appropriate interval, clean each lubrication
fitting indicated on the Lubrication
Chart
and
Service
Maintenance Schedule. Use a pressure gun
to lubricate. Be sure the grease channels are open
to provide complete lubrication of bearing surfaces.
In
some
cases it may be necessary to disassemble
to clear plugged channels.

When
vehicles are driven primarily in abnormally dusty or wet areas or when a vehicle is subject to
severe operating conditions, perform
these
services
more frequently. Under
these
conditions, no definite interval can be recommended because of the great variety of
uses
and conditions of use. 11

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

B
e.
Check
for the presence of
excess
water in the

oil
that might indicate an internal leak from the
cooling system.

f.
Pour oil into the oil filler tube. Replace the oil

filler
cap.

B-10.
Engine Oil
Filter
Service —
Hurricane
F4 Engine

The
engine
oil filter assembly should be replaced at each
2000
miles
[3.200
km.] of normal
engine

use. To remove the filter, use oil filter wrench
C-4065.
To install a new filter, wipe the gasket —
contact surface with
engine
oil, screw on the unit

until
gasket contacts the sealing surface, and then tighten at least one
half
turn
more. DO NOT USE

TOOLS.
Turn
by hand only. When refilling the
engine
crankcase after filter has been changed be

sure
to add one extra quart [1 ltr.] of oil to
fill

filter
and oil passages. Run
engine
to make sure there is no leak at oil filter.

B-l 1.
Engine Oil
Filter
Service — Dauntless V-6 Engine

To
replace the oil filter, use oil filter wrench, Tool

C-4065,
to remove the filter. After the filter has
been removed from the oil pump housing located
on the right front side of the engine, wipe the
housing surface clean and oil the gasket on the base of the new filter to make a
good
seal. Screw
the new filter in position until its gasket contacts
the pump housing surface, then tighten at least
one-half
turn
until filter fits snug.

Note:
Tighten by hand only, do not use a tool to
tighten.

Replace
oil filter each
6000
miles
[9.600
km.] at

engine
oil change.

B-12.
Exhaust
Manifold
Heat
Control
Valve
— Dauntless V-6 Engine

A
thermally-actuated heat control valve is located at
rear
of the right exhaust manifold of the Daunt­

less
V-6 engine.
This
valve has a bimetal thermo­
static spring which holds the valve closed when
the
engine
is cold.

Each
time the vehicle is lubricated place a few drops of penetrating oil on the valve shaft bushings

and
then work the valve by hand making sure that
the lubricant is worked into the bushings.

Note:
If the valve shaft
does
not operate freely
penetrating oil should be used to free the shaft.

B-l 3.
Positive
Crankcase
Ventilation
System

Service
the ventilation system of the
engine
each
multiple of
6000
miles
[9.600
km.] on the odometer
after
initial
2000
miles
[3.200
km.] service. Re­
place the ventilation valve each
12,000
miles
[19.200
km.].

For
information on servicing the positive crankcase
ventilation system on the
Hurricane
F4
engine
and
the Dauntless V-6 engine, refer to the Tune-up Section.

B-l4.
Distributor
— Hurricane F4 Engine

The
distributor shaft is lubricated through an oiler mounted on the side of the housing. Place three or four drops of light
engine
oil in the oiler each
2,000

miles
[3.200
km.]. Also place one drop of light
engine
oil on the wick located on the top of the
shaft, which is made accessible by removing the
rotor
arm. Sparingly apply cam lubricant to the
breaker
arm cam and place a drop of oil on the

breaker
arm pivot.

B-l
5.
Distributor
— Dauntless V-6 Engine

The
distributor has a lubricant reservoir that
car­

ries
sufficient
lubricant
for the life of the distributor.
When
servicing breaker points, place one drop of
light
engine
oil on the wick located on the top of the shaft Also, apply cam lubricant sparingly to
the breaker arm cam, and place a drop of oil on the

breaker
arm pivot.

B-l6.
Generator

On
early production vehicles oilers are provided
at each end of the generator, for lubrication
pur­

pose.
On late production vehicles one oiler is pro­
vided at the
rear
(bushing end) of the generator for lubrication purpose. Place two to four drops of
light
engine
oil in each oiler every
2,000
miles
[3.200
km.].

B-l
7. Spark Plugs

Replace
spark
plugs. Refer to Section C.

B-18.
Starting
Circuit

Check
the starting
circuit.
Refer to Section H.

B-l
9. Charging
Circuit

Check
the charging
circuit.
Refer to Section H.

B-20.
Engine Tune-Up

Refer
to Section C of this manual.

B-21.
Adjust
Fan
Belt

Refer
to Section C.

B-22.
Exhaust Emission
Control
System or
Controlled
Combustion System

•
Refer to the appropriate section in this manual.

B-23.
Exhaust System

Check
the exhaust system for leaks. Refer to Section F.

B-24.
Fuel Evaporative Emission
Control
Canister Air
Filter

The
only service required for the
F.E.E.C.
system
is cleaning the air cleaner filter mounted at the
bottom
of the canister. The filter requires replace­
ment at
12,000
mile intervals. Refer to Section

E,
Par. E-9 for service procedure.

B-25.
Oil Bath Air Cleaner
Some 'Jeep' Universal vehicles are equipped with

an
oil bath type air cleaner.
This
type air cleaner
thoroughly removes all dust from the air before it enters the carburetor, if it is properly serviced.

When
the vehicle is operated under normal condi­
tions the air cleaner must be serviced at regular

intervals
as care of the air cleaner is extremely 13

'Jeep9
UNIVERSAL
SERIES
SERVICE
MANUAL

h.
Check
ignition (distributor) timing; reset if
necessary.

i.
Check
carburetor
adjustments; reset if necessary,

j.
With
engine
fully warmed up, tighten cylinder
head and manifold
bolts
and nuts to specified
torque.
Check
cylinder head gaskets and
bolts
for
air
or coolant leaks.

Note:
Tightness of cylinder head
bolts
should be
checked and corrected after 500 to 600 miles [800

a
960 km.] of normal operation.

k.
Check
fan belt tension; adjust if necessary.

I.
Check
for and correct any oil leak, fuel leak or
coolant leak.
D-107.
VALVE
ADJUSTMENT

Proper
valve adjustment is important to prevent
burning
of valves and poor
engine
performance.

This
adjustment consists of obtaining a specified

lash
in the valve mechanism. The exhaust valve
tappets and the intake valve rocker arms should be adjusted to the proper clearance with the
engine

cold (at room temperature). Valve clearance can
be properly adjusted only when the tappet is on the
heel or low portion of the cam.
INTAKE

OPENS

9°
BTC?

FIG.
D-43-
10270

-VALVE
TIMING
D-108. Valve Adjustment Procedure

The
exhaust valve tappets are adjusted by turning
the adjusting screw in or out of the tappet as neces­
sary
to obtain the proper clearance. Where special
wrenches can be obtained, they should be used to facilitate the adjustment. The proper clearance is .016" [0,406 mm.]
between
the end of the adjusting
screw and the
bottom
of the exhaust valve.

Crank
the
engine
over to
close
a valve and check
the clearance with a feeler
gauge.
To adjust, hold
the tappet with one wrench and
turn
the adjusting

screw,
with the other.
Check
and adjust each of
the tappets in proper sequence.

Adjust
each intake valve by adjusting the rocker
arm
screw at the push rod to obtain .018" [0,457 mm.] clearance
between
the rocker arm and the
valve stem with tappet on the heel of the cam.
D-109.
Check
Valve
Timing

To
check the valve timing, carefully set the intake
valve rocker arm adjustment for No. 1 cylinder to .026"
[0,6604
mm.]
between
the rocker arm and the
valve stem. Rotate the crankshaft clockwise until
the piston in No. 1 cylinder is ready for the intake stroke. The intake valve
opens
9° before top center
(BTC).
Note
the distance
between
the
"TC"
and
"5°"
marks on the indicator on the timing gear
cover and estimate the 9° before top center position.
See
Fig.
D-43.
With
the crankshaft in this position, timing is correct if the rocker arm is just tight
against the intake valve stem. Do not overlook resetting the rocker arm adjustment to the correct

running
clearance.
D-110. Positive
Crankcase
Ventilation

Be
sure there are no air leaks at the tube connec­
tions
between
the air cleaner and the oil filler tube,

and
that the oil filler tube cap gasket is in
good

condition. Always keep the cap locked securely in
place. When tuning the
engine
or grinding valves, remove the control valve and clean it thoroughly.
If
the valve is blocked with carbon, the ventilating
system
will
not operate and, should the valve

fail
to seat, it
will
be impossible to make the
engine

idle satisfactorily. Refer to Par. C-6 for servicing.
D-111. Oil
Filter

The
engine
is equipped with a throw-away type

oil
filter.
This
oil filter must be serviced periodi­
cally
as outlined in the
Lubrication
Section. 69

'Jeep*
UNIVERSAL SERIES SERVICE
MANUAL

Dl

12710

FIG.
D1
-3—HYDRAULIC VALVE
LIFTER
ASSEMBLY, CROSS-SECTIONAL VIEW
1—
Snap
Ring
6—Ball Retainer

2— Rod
Seat
7—Plunger Spring

3—
Oil
Inlets
8—Lifter
Body

4—
Plunger
9—Bronzed
Cap
5— Feed
Hole
sages
in the block and cylinder head.

The
water cooled system is pressurized to provide efficient
engine
cooling. It consists of a centrifugal-
type water pump, mounted on the timing chain cover, and is driven by the
engine
fan pulley. The
pump provides coolant flow equally to both
cylin­
der banks under control of a thermostat. Coolant
flow is around the cylinders and through the
cylinder
head to dispel the heat of combustion in
the engine.

Dl-3.
Engine Mounts

The
engine-transmission unit is mounted to the chassis at three points by rubber pads. The two
front mounts are bolted to the
engine
cylinder
block and the frame members. These mounts sup­ port most of the
engine
weight, and absorb
vibra­

tion which would otherwise be caused by changes
in
engine
output torque. The single
rear
mount is
placed
between
the transmission and the trans­ mission support. It supports part of the engine'

and
transmission weight, and locates the
rear
of
the
engine
with respect to the centerline of the
vehicle.

Dl-4. ENGINE REMOVAL
To
remove the
engine
from the vehicle follow the
procedurers listed below:

a.
Remove hood. b. Disconnect battery cables from battery and
engine. c. Remove air cleaner.

d.
Drain
coolant from radiator and engine.
e.
Drain
engine
oil.
f. Disconnect alternator wiring harness from con­ nector at regulator.

cj.
Disconnect the fuel evaporative purge line con­ nected to the
P.C.V.
valve.

h.
Disconnect upper and lower radiator
hoses
from
the engine.

i.
Remove right and left radiator support
bars,

j.
Remove radiator from the vehicle.

k.
Disconnect
engine
wiring harnesses from con­
nectors located on
engine
firewall.
I.
On
engines
equipped with exhaust emission con­

trol,
remove the air pump, air distribution manifold,

and
anti-backfire (gulp) valve. See Section F2 for
procedure.

m.
Disconnect battery cable and wiring from en­

gine
starter assembly.

n.
Remove
engine
starter assembly from engine,

o.
Disconnect
engine
fuel
hoses
from fuel lines at

right
frame
rail,
p. Plug fuel lines.

q.
Disconnect choke cable from carburetor and cable support bracket mounted on engine,
r.
Disconnect exhaust pipes from right and left

engine
manifolds.
s. Place
jack
under transmission and support trans­
mission weight.
f. Remove
bolts
securing
engine
to front motor mounts.

u.
Attach suitable sling to
engine
lifting
eyes
and,
using hoist, support
engine
weight.
v. Remove
bolts
securing
engine
to flywheel housing.
w. Raise
engine
slightly and slide
engine
forward
to remove transmission main shaft from clutch plate spline.

Note:
Engine and transmission must be raised
slightly to release the main shaft from the clutch
plate while sliding the
engine
forward.
x. When
engine
is free of transmission shaft raise

engine
and remove from vehicle,
y. Place
engine
on suitable blocking or
engine
stand and remove sling from engine.

Dl-5.
ENGINE DISASSEMBLY

Engine
disassembly is presented in the sequence to be followed when the
engine
is to be completely
overhauled after removal from the vehicle. Some of the operations of the procedure are also appli­cable separately with the
engine
in the vehicle,
provided that wherever necessary the part of the
engine
to be worked on is first made accessible by removal of
engine
accessories or other parts.

When
the disassembly operations are performed
with
the
engine
out of the vehicle, it is assumed,
in
this procedure, that all of the accessories have
been removed
prior
to starting the disassembly and
the oil has been drained.

E

FUEL
SYSTEM

9
©

FIG.
E-4—FUEL
EVAPORATIVE
EMISSION
CONTROL
SYSTEM-
DAUNTLESS
V-6
ENGINE
A—Side
View
1—
Charcoal
Canister

2—
P.C.V.
Crankcase
Valve

3—
Purge
Line

4—
Fuel
Tank
5—
Fuel
Filler
Hose
B—Plan
View
6—
Non-Vented
Gas Cap 7—
Vapor
Separator or Expansion
Tank

g—Fuei
Gauge

9—Fuel
Line-to-Fuel
Pump

10—Fuei
Return
Line

during
normal temperature vehicle operation, thus
minimizing
driveability problems. An additional
feature of this valve is a built-in vacuum relief

which
allows inward air flow under negative fuel

tank
pressure conditions. The valve housing con­
tains the normal tank vent and purge connections.

E-5.
Fuel Tank

The
fuel tank is external expansion type.
Fuel

tank
venting is accomplished by several vapor
lines which lead to the vapor separator or expan­
sion tank. The vapor lines which lead from the
fuel tank are located at the front and
rear
so that
during
any inclination of the vehicle, at least one
line
will
be open to vent at all times.
E-6.
Vapor Separator
or
Expansion Tank

The
vapor separator is chambered so that the
rear
fuel tank vent lines lead into a separate chamber

with
a fuel shutofl valve.
This
prevents solid fuel
from
flowing from the fuel tank to the vapor can­
ister during uphill operation or parking of the
vehicle. A single vapor vent line leads from the fuel
vapor separator to the vapor collection canister
where fuel vapors are stored until they can be drawn into the
engine
and burned.

The
expansion tank allows expansion of the fuel as

required
during temperature changes and simul­ taneously
becomes
a liquid trap that only allows
vapors to pass.
E-7.
Sealed
Gas Cap

The
sealed gas cap is designed to allow no vapors to
discharge into the atmosphere under normal
operation of the system. If the system
becomes
plugged or a failure of the demand valve occurs 112

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

E
there is a relief valve that
opens
to reduce high
(dangerous) pressures in the fuel tank. In con­

junction
with the pressure relief valve there is a
vacuum
relief valve to
stop
collapse of the fuel

tank
in case of a plugged system or failure of the demand valve. When replacing the gas cap, the
same type must be used as originally installed.

E-8.
System Inspection Test

The
fuel emission vent system should be checked

carefully
to ensure the absence of any leaks to the
atmosphere of either liquid or vapor which might
affect the accuracy, safety, or performance of the control system.

To
assure that the sealed system has been properly

installed,
the following
test
procedure has been
developed.
Disconnect the vent line from the fuel tank system
to the activated charcoal canister, induce l/i p.s.i.
air
pressure. If this pressure can be maintained for

a
few seconds the vent system is assured to be sealed. DO NOT add air pressure to the canister
because damage can occur to the demand valve if
care
is not taken.

E-9.
Servicing the System

Periodic
Maintenance — Replace carbon canister filter at
12,000
miles
[19,200
km.] or 12 month in­tervals (more
often
for operation in dusty areas).

This
is the only regular maintenance service

required.

Canister
Filter
Replacement — Disconnect
hoses

from
top of canister, remove canister from mount
-

t
FIG.
E-5—CARBURETOR—
F4 ENGINE,
EARLY
MODEL
1—
Choke
Clamp
Bracket

2—
Choke
Shaft and
Lever
Assembly

3—
Fuel
Inlet
Elbow

4—
Bowl
Vent Tube 5—
Idle
Air Adjusting
Needle
6—
Throttle
Lever
and Shaft Assembly
7—
Idle
Speed Adjusting Screw
8—
Fast
Idle Connector Rod ing bracket. Remove cover from
bottom
of canister
by pulling it down to
disengage
clips. Remove and
discard
polyurethane filter element
(squeeze
ele­

ment out from under retainer bar).
Install
new
filter by squeezing element under retainer bar and positioning it evenly around entire
bottom
of
canister with
edges
tucked under canister lip, snap

bottom
cover in place, reinstall canister on bracket

and
reconnect
hoses.

Vapor
line
hoses
used in this system are made of

special
rubber material.
Bulk
hoses
are available for
parts
service.
Ordinary
rubber
hose
should not be
used to service vapor lines as they are subject to deterioration and may clog the system.
Liquid

vapor separators or expansion tanks and canisters

are
serviced as complete units only.
Canister
air filters, however, are serviced separately.

E-10.
CARBURETOR
—
HURRICANE
F4
ENGINE

A
single-barrel manual choke, down-draft carbure­
tor (Fig. E-6) is used on the
Hurricane
F4 engine.
The
carburetor is internally vented by a tube
opening located in the air horn body of the
car­

buretor.
This
opening is connected by a rubber
tube to the air
outlet
horn of the air cleaner thus
allowing only filtered atmospheric pressure air
to enter the float chamber for balance pressure
of the carburetor fuel.

Note:
A carburetor with a specific flow character­

istic
is used for exhaust emission control. The
carburetor
is identified by a number, and the correct

carburetor
must be used, when replacement is
necessary.

Early
production models
CJ-3B,
CJ-5,
CJ-5A,
CJ-6,
and
CJ-6A
have a
Carter
YF-938SD
carbure­
tor superseding the earlier
YF-938SC,
YF-938SA,

or
YF-938S
models.

Note."
Conversion kits for changing earlier models
to SD models are available. See Par E-23. It is recommended that when a carburetor is converted
that a tag be fashioned stamped with the new model number and installed under one of the air

horn
screws.
Look
for such a tag to determine if
the carburetor has previously been converted.

Carburetors
listed above are all in the same YF
series and have only minor differences. Descriptions
and
repair procedures given in the following
para­
graphs apply equally to all
YF-series
carburetors.
YF-series
carburetors employ manual and vacuum
control of the metering rod and accelerator pump.
The
carburetor controls and vaporizes the fuel
through five separate systems: float system, low-
speed system, high-speed system, choke system,

and
accelerating-pump system. A description of the function and operation of each system provides an over all description of the carburetor.

For
identification, the series designation is stamped
on the body under the name
Carter
and the model
designation is stamped on a flange protruding
from
the body.

Note:
When checking for carburetor icing causes,
also check the vacuum-pump-to-manifold vacuum
line connector. 113

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

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

E

FIG.
E-14—DRILLING CARBURETOR JET 1—
Drill
(#68 size)

2—
Accelerator
Pump Discharge Jet
E-24.
Steep-Grade
Carburetor
Kit

In
the
field
where a vehicle equipped
with
Carter carburetor 938-S is required to
idle
on
steep

slopes,
flooding
of the carburetor sometimes results.

A
steep-grade
carburetor kit is available that
will

allow satisfactory
idle
operation under this condi­

tion.
This kit (Part
No.
#94481,
Carter # 75-960U)
contains a metering rod, a metering rod jet, and a
plug.

To
install
this kit, replace the standard metering

rod
and metering rod jet
with
those
contained in the
kit.
Place the small
brass
plug
in the accelerator
pump
well.
Exert
finger pressure only when in­

stalling
this
plug.
Forcing the
plug
in too far
will
damage
the accelerator
jet.
Make certain the meter­

ing
rod and
float
level
are set to specifications.

When
reworking
the carburetor to include this
steep-grade
kit, check to determine if the seal (Carter #121-172) and retainer (Carter #136-152)
are installed. If
these
parts are not present, they

should
be installed.
FIG.
E-15—CARBURETOR-
DAUNTLESS V-6 ENGINE 1—
Fuel
Inlet

2—
Choke

3—
Choke
Cable
Bracket

4—
Idle
Speed Adjusting Screw 5—
Idle
Fuel-air
Mixture Screws
E-25.
CARBURETOR
—
DAUNTLESS
V-6

ENGINE

A
double-barrel, manual choke, down-draft car­
buretor (Fig. E-15) is used on the Dauntless V-6 engine.
Note: A carburetor
with
a specific
flow
character­

istic
is used for exhaust emission
control.
The
carburetor is
identified
by a number, and the
correct carburetor must be used, when replacement
is
necessary.

The carburetor
fuel
bowl
is located
forward
of
the main bores. The carburetor is compact in design

in
that all of the
fuel
metering is centrally located.
See Fig. E 16.

This
carburetor
uses
a calibrated cluster design

with
main
well
tubes,
idle
tubes, mixture
passages,
air
bleeds and pump jets in one removable as­

sembly.
This cluster assembly can be easily re­

moved
for cleaning and inspection purposes. It is

mounted
on a
flat
portion
of the carburetor
bowl

in
front
of the main
venturi.
The
idle
and main

well
tubes
are precision
pressed
fit in the cluster
body.
They cannot be serviced separately. The

main
nozzles and
idle
tubes
are
suspended
in the
main
wells of the
float
bowl.

The main metering jets are of the
fixed
type. A
system of calibrated air bleeds gives correct
fuel-

air
mixture throughout all operational
ranges.
This
carburetor has a vacuum-operated power sys­

tem
which
supplies extra
fuel
when needed. Power
mixtures
are regulated by drop in engine
manifold
vacuum,
regardless of throttle opening. Thus, addi­

tional
fuel
is supplied for power mixtures accord­

ing
to engine demands.
The accelerator pump plunger has a vapor vent

ball
in its head. This
ball
and its
seat
form
a valve

to
vent any
fuel
vapors
which
form
in the pump

well
to the
fuel
bowl
during hot-engine operation.
This
ensures
that the pump
well
and
passages
will

be primed
with
solid
fuel
at all times and im­ proves accelerator pump action. The carburetor is
internally
vented through a hole

in
the air horn.
FIG.
E-16—FUEL BOWL BODY—TOP VIEW
1— Pump Return Spring 3—Power
Valve
2—
Main
Metering
Jets
4—Cluster Assembly
119

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

E
possibility of vapor lock by keeping cool fuel from
the tank constantly circulating through the fuel
pump.

Fuel
pump pressure at carburetor (inlet) on Daunt­
less
V6-225
engine
should be 3% lbs.
[0,264
kgm-cm2] minimum at idle with the vapor return
hose

squeezed off. With the vapor return
hose
open
pump pressure should be 2j^ lbs. [0,176 kg-cm2]
minimum.

The
Dauntless V-6
engine
is equipped with a sealed

unit,
non-repairable, single-action fuel pump (Fig.

E-33).

Note:
All Dauntless V-6
engines
are equipped with

a
throw-away can-type gasoline filter installed in
the fuel line
between
the fuel pump and the
car­
buretor.
This
unit must be replaced every
12,000
miles
[19.200
km.] of vehicle operation.

E-68.
Fuel
Pump Removal

To
remove the fuel pump from the Dauntless V-6
engine, disconnect the fuel inlet, fuel
outlet
and fuel return lines from the pump. Remove the two
fuel pump body attaching cap screws and lock

washers.
Pull
the fuel filter bracket free and remove the pump and gasket. Discard pump and gasket.
Install
new pump in reverse procedure of removal.

E-69.
AIR
CLEANER

Servicing
of the air cleaner is properly taken care of as part of the periodic lubrication and servicing of the vehicle. For this reason, air cleaner servicing
information is given in the Lubrication Section.

Refer
to and follow the instructions given there.

E-70. ACCELERATOR LINKAGE
The
accelerator linkage is properly adjusted when
the vehicle leaves the factory. However, in time
components parts
will
become
worn and require re­
adjustment to maintain a smooth even control of
engine
speed. On Models equipped with F4
engines

the adjustment is made at the adjusting block,

Fig.
E-34. Loosen the lock nuts, and adjust the length of the accelerator rod so that when the
car­

buretor throttle valve is wide open the accelerator
treadle
will
just strike the toe board. After correct
adjustment is made tighten both lock nuts firmly.
To
adjust the accelerator linkage on V6
engines

loosen
the lock nuts securing the accelerator rod
housing to its securing bracket and adjust the length
of the accelerator rod so that when the carburetor throttle valve is wide open the accelerator treadle

will
just strike the toe board. After correct adjust­
ment is made, tighten lock nut firmly, see Fig. E-35 for Dauntless V-6 engine.

E-71. FUEL
TANK
AND
FUEL LINES
The
following paragraphs (E-70 through E-73) describe the removal, installation and services to
be performed when replacing the fuel tank or
servicing
the fuel system.

FIG.
E-34—ACCELERATOR LINKAGE,
F4
ENGINE
1—
Grommet

2— Nut and Lockwasher

3—
Throttle
Control
4—
Choke
Control 5—
Treadle
Rod Seal
6—
Accelerator
Treadle
7—
Treadle
Hinge Pin
8—
Treadle
Hinge 9— Nut and Lockwasher
10—
Screw

11—
Accelerator
Rod
12— Nut
13—
Adjusting
Block
14—
Retracting
Spring
15—
Cotter
Pin
16—
Lower
Beilcrank
17—
Washer

18—
Beilcrank
Link
Rod
19—
Bracket

20—
Throttle
Wire
Stop
21—
Beilcrank
Spring
22—
Rod

23—
Upper
Beilcrank
24—
Wesher
10731
131

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

E
portant that
these
lines are not accidentally re­
versed.

When
installing the fuel tank on late model vehicles, position the tank
between
the frame
rail

to allow space to connect the fuel line(s), vent
hose

and
sending unit wire. After connecting
these
items, align and secure tank to frame brackets.
Position filler
hose
on tank filler neck and tighten
hose
clamp.
Fill
tank with fuel and check for leaks.

When
installing the fuel tank on early model vehicles, reverse the order of removal as given in

Par.
E-73.

E-75.
Fuel
Tank
Cap

A
surge pressure type fuel tank filler cap is used on

all
models.
This
is necessary to prevent fuel leakage
from
the cap vent opening when the vehicle is on a
side slope. Two spring loaded relief valves which
open when venting is required are built into the
cap.
Should the pressure valve
fail
to open, pressure
in
the tank may force fuel by the carburetor inlet
valve causing flooding.
Failure
of the vacuum valve may prevent flow of fuel to the carburetor. Should
the valves
fail
to vent install a new cap.

Note:
Vehicles having a
Fuel
Evaporative
Emis­

sion System are equipped with a non-vent sealed gas cap. The sealed cap is designed to allow no
vapors to discharge to the atmosphere. No other type of cap is to be used on vehicles having this
type system.

E-76.
Fuel
Gauge Float Unit

The
fuel tank
gauge
float unit is mounted in the top
of the fuel tank and consists of a housing enclosing
a
rheostat that is actuated by the float arm, and a
float
which
moves
with the fuel level in the tank.
On
V-6 and current production F4
engine
equipped vehicles, the fuel
outlet
pipe is integral with the
float
unit.
The fuel
outlet
pipe has a mesh filter on the inner end.

Note:
Under no circumstances should a fuel tank

gauge
be installed without a mesh filter element.

The
filter,
outlet
pipe, and float unit are locked as

an
assembly to the top of the fuel tank. To remove,

turn
the lock plate that secures the float unit
assembly.

E-77.
Fuel
Lines

Check
lines and connections occasionally for leaks,
and
for severe kinks that might restrict the flow of
fuel. If an excessive amount of
dirt
is found in the
carburetor
or fuel pump, the fuel tank should be
drained
and the fuel lines blown out with com­
pressed air.

All
rubber fuel lines and their respective clamps should be checked occasionally to be certain they
are
correctly positioned and not leaking. 133