1953 JEEP DJ ignition

D

HURRICANE
F4
ENGINE
D-112.
SERVICE
DIAGNOSIS

Poor
Fuel
Economy Ignition Timing Slow or Spark Advance Stuck

Carburetor
Float High
Accelerator Pump Not Properly Adjusted
High
Fuel
Pump Pressure

Fuel
Leakage
Leaky
Fuel
Pump Diaphragm
Loose Engine Mounting Causing High
Fuel
Level

in
Carburetor

Low
Compression Valves Sticking

Spark
Plugs Bad

Spark
Plug Cables Bad Weak
Coil
or Condenser Improper Valve Tappet Clearance

Carburetor
Air Cleaner Dirty
High Oil Level in Air Cleaner Dragging Brakes

Front
Wheels Out of Alignment
Tires
Improperly Inflated Inaccurate Odometer

Faulty
Fuel
Tank
Cap

Clogged
Muffler or Bent Exhaust Pipe

Lack
of Power
Low
Compression Ignition System (Timing Late)
Improper Functioning Carburetor or
Fuel
Pump

Fuel
Lines
Clogged
Air
Cleaner Restricted
Engine Temperature High Improper Tappet Clearance
Sticking Valves Valve Timing Late

Leaky
Gaskets
Muffler
Clogged
Bent Exhaust Pipe

Defective
Spark Plugs—Clean or Replace
Defective
Breaker Points—Replace
Points

Incorrect Breaker Point Gap—Reset
Points

Defective
Condenser or Coil—Replace
Loose Electrical Connections—Locate and Tighten
Broken Valve Spring—Replace Spring Broken Piston or Rings—Replace
Defective
Head Gasket—Replace Gasket
Cracked
Distributor Cap—Replace Cap

Low
Compression
Leaky
Valves
Poor Piston Ring Seal Sticking Valves
Valve Spring Weak or Broken
Cylinder
Scored or Worn
Tappet Clearance Incorrect
Piston Clearance too Large
Leaky
Cylinder Head Gasket
Burned Valves and
Seats
Sticking Valves or too Loose in Guides Improper Timing
Excessive Carbon Around Valve Head and Seat Overheating
Valve Spring Weak or Broken Burned Valves and Seats—Continued
Valve Tappet Sticking
Valve Tappet Clearance Incorrect
Clogged
Exhaust System
Valves Sticking Warped Valve Improper Tappet Clearance
Carbonized or Scored Valve
Stems
Insufficient Clearance Valve Stem to Guide
Weak or Broken Valve Spring Valve Spring Cocked Contaminated Oil
Overheating Inoperative Cooling System
Thermostat Inoperative Improper Ignition Timing
Improper Valve Timing
Excessive Carbon Accumulation

Fan
Belt too Loose

Clogged
Muffler or Bent Exhaust Pipe

Oil
System Failure
Scored or Leaky Piston Rings

Popping-Spitting-Detonation
Improper Ignition
Improper Carburetion
Excessive Carbon
Deposit
in Combustion
Cham­
bers
Poor Valve Seating Sticking Valves
Broken Valve Spring Tappets Adjusted too Close

Spark
Plug Electrodes Burned
Water or Dirt in
Fuel
Clogged
Lines Improper Valve Timing
Excessive Oil Comsumption Piston Rings Stuck in Grooves, Worn or Broken Piston Rings Improperly Fitted or Weak Piston Ring Oil Return
Holes
Clogged
Excessive Clearance, Main and Connecting Rod
Bearings

Oil
Leaks at Gaskets or Oil Seals
Excessive Clearance, Valve Stem to Valve Guide (Intake)

Cylinder
Bores Scored, Out-of-Round or Tapered Too Much Clearance, Piston to Cylinder Bore
Misaligned Connecting Rods
High Road
Speeds
or Temperature
Crankcase
Ventilator Not Operating
Bearing Failure
Crankshaft
Bearing Journal Out-of-Round

Crankshaft
Bearing Journal Rough

Lack
of Oil
Oil
Leakage
Dirty
Oil

Low
Oil Pressure or Oil Pump Failure
Drilled
Passages
in Crankcase or Crankshaft
Clogged

Oil
Screen Dirty Connecting Rod Bent 70

Dl

DAUNTLESS
V-6
ENGINE
In
addition to the instructions covering operations
for disassembling the
engine
out of the vehicle, special instructions are given to cover different
operations required when disassembly is
done
with
the
engine
installed.

During
disassembly operations, the
engine
should be mounted in a suitable
engine
repair stand.

Where
practicable, modify or adapt an existing re­

pair
stand as necessary to accommodate the
engine.
If
an
engine
repair stand is not used, take care to

perform
disassembly operations in a manner that
will
protect personnel against an accident and the
engine
and its parts against damage.

Dl-6.
Mounting Engine
On
Engine Stand

Refer
to Fig. Dl-4.
a.
With
the
engine
supported by a hoist, remove
the clutch housing and clutch. Match
mark
the flywheel and the clutch cover before disassembly to assure proper reassembly.
b. Position the
engine
on the
engine
stand.
c. Release
some
tension of the hoist cables and secure
engine
to stand.

d.
Make sure the position lock on the
engine
stand
is tight to prevent the
engine
from accidentally
inverting.

e.
Release the hoist cables.
FIG.
D1
-4—ENGINE
MOUNTED
ON
STAND

1—
Spacer
J-8690-6
A—Bolt,
i/2-NC
x 3i/2"

2—
Bolt,
3/a-NC
x 4*/2" 5—Adapter 21316-J 3—
Engine
Mounting Stand
Dl-7.
Remove Intake Manifold
and

Carburetor Assembly

Disconnect crankcase vent
hose,
distributor vacuum

hose,
and fuel line from carburetor. Disconnect two distributor leads from ignition coil. Disconnect

wiring
harness from coolant temperature sending

unit.
Remove ten cap
bolts
which attach intake
manifold to cylinder heads. Remove intake mani­
fold assembly and gaskets from
engine.

Dl-8. Remove Exhaust Manifold
The
engine
has two exhaust manifolds. Remove five attaching screws, one nut, and exhaust mani­
fold from each cylinder head.

Dl-9.
Remove Distributor

Disconnect vacuum
hose
and wiring harness from

distributor.
Disconnect spark plug cables from
spark
plugs. Remove sparks plugs from
engine.
Pull

spark
plug cable retainers from brackets on rocker

arm
covers. Remove mounting screw, retainer

bracket,
and distributor from timing chain cover.
If
timing chain and sprockets are not to be re­
moved from
engine,
note
position of distributor
rotor so that it can be installed in identical position.

Dl-10. Remove
Fuel Pump
Disconnect output fuel line from fuel pump. Re­
move
two mounting bolts, fuel pump, and gasket

from
timing chain cover.

Dl-11.
Remove Alternator
and Fan
Belt

Disconnect wiring harness from alternator. Remove nut and flat washer which fasten alternator to
adjustment bracket. Pivot alternator
inward,
to­

ward
engine
cylinder block, to relieve fan belt
tension. Remove fan belt from pulleys. Remove
two attaching screws, mounting bracket, and alter­ nator from right cylinder head of
engine.

Dl-12.
Remove Cooling
Fan and
Water Pump

Refer
to Fig. Dl-5.
Remove four cap screws, lock washers, cooling fan,

fan
hub, and fan drive pulley from flange of water
pump shaft. Remove nine attaching screws, water
pump, alternator adjustment bracket, and water pump from timing chain cover.

Dl-13.
Remove
Oil
Filter

Unscrew
oil filter from
engine
oil pump.

Dl-14.
Remove Starter Motor

Disconnect wiring harness from starter motor and
solenoid. Remove two attaching screws, starter motor, solenoid, and motor attaching bracket from

engine
flywheel housing and cylinder block.

Dl-15.
Remove
Oil
Pressure Sending Unit

Disconnect wiring harness from oil pressure send­
ing unit. Remove oil pressure sending unit from

engine
cylinder block.

Dl-16.
Remove
Oil
Dipstick

Withdraw
and remove oil level dipstick and dip­

stick
tube
from
engine
cylinder block.

Dl-17.
Remove Crankshaft Pulley

Remove six attaching screws and crankshaft pulley

from
crankshaft vibration damper. 80

Dl

DAUNTLESS
V-6
ENGINE
e.
Connect electrical wiring harness to coolant
temperature sending unit. Connect two distributor leads to ignition coil. Connect fuel line
between

fuel pump and carburetor, vacuum
hose
between
distributor and carburetor, and crankcase vent
hose

to intake manifold
below
rear
of carburetor.
FIG.
D1-46—-INTAKE
MANIFOLD
INSTALLATION

1—Long Bolt 2—Open Bolt Hole
Dl-102.
ENGINE INSTALLATION

Install
the
engine
in the vehicle in the following
procedure listed
below:

a.
Attach suitable sling to
engine
lifting
eyes
and,
using a hoist, lift the
engine
from blocks or
engine
stand.
b. When
engine
is free of the stand lower it slowly

into
the
engine
compartment of the vehicle.

Note:
The
engine
and transmission must be lined
up to
engage
the main shaft and clutch plate spline
while sliding the
engine
rearward
into
the mounting
position.
c.
Install
and tighten up
bolts
securing
engine
to
flywheel housing.

d.
Install
and tighten front
engine
mounting bolts.

e.
Remove sling from the
engine.

I.
Connect exhaust pipes to right and
left
engine
manifolds.
g. Connect choke cable support bracket to
car­

buretor.

h.
Connect
engine
fuel
hoses
and fuel lines at right
frame
rail.

I.
Connect fuel lines.

j.
Mount
engine
starter motor assembly to
engine.
k.
Connect battery cable and wiring to
engine

starter
motor.

I.
Connect
engine
wiring harnesses to connectors
located on
engine
firewall.

Note:
On
engines
equipped with exhaust emission
control, replace the air pump, air distributor mani­
fold, and anti-backfire (gulp) valve. See Section F2.
m. Replace radiator, and secure with bolts,
n.
Replace and tighten right and
left
radiator sup­
port rods.
0. Connect upper and lower radiator
hoses
to the

engine.
p. Connect alternator wiring harness from connec­
tor at regulator,
q.
Replace air cleaner.
r.
Connect battery ground cable from the battery
to the
engine
and the
engine
ground strap,

s.
Replace the hood.

After
the
engine
is installed in the vehicle,
fill
radiator
with coolant and
engine
with oil (Refer to
Lubrication
Section B), then perform an
engine

Tune-up
and road
test
(Refer to Tune-up Sec­
tion C).

Dl-103.
FINAL IN-VEHICLE ADJUSTMENTS

a.
Clean
battery terminals and check battery.
b.
Check
ignition wires and connections.
c. Service carburetor air cleaner.

d.
Service positive crankcase ventilation valve.
e.
Check
fuel lines.
f. Gap and install new
spark
plugs.
g.
Check
distributor
points
and capacitor; replace
if
necessary.

h.
Check
ignition (distributor) timing; reset if
necessary. 1.
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 miles [800 km.]
of normal operation and again at 1000 miles [1600

km.].
k.
Check
fan belt tension; adjust if necessary.
I.
Check
for and correct any oil leak, fuel leak or
coolant leak. 104

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

Dl
Dl-104.
SERVICE
DIAGNOSIS

Poor Fuel Economy
Ignition Timing Late or Spark Advance Inoperative

Carburetor
Float Setting Too High
Accelerator Pump Improperly Adjusted
Fuel
Pump Pressure High

Fuel
Line
Leakage

Fuel
Pump Diaphragm Leakage
Cylinder
Compression Low
Valves Do Not Seat Properly
Spark
Plugs
Defective

Spark
Plug Cables
Defective

Ignition
Coil
or Capacitor
Defective

Carburetor
Air Cleaner Dirty

Brakes
Drag
Wheel Alignment Incorrect

Tire
Pressure Incorrect Odometer Inaccurate

Fuel
Tank
Cap Clogged or
Defective

Muffler or Exhaust Pipe Clogged or Bent

Lack
of
Power
Cylinder
Compression Low
Ingitdon Timing Late

Carburetor
or
Fuel
Pump Clogged or
Defective

Fuel
Lines Clogged
Air
Cleaner Restricted
Engine Temperature High Valves Do Not Seat Property

Valve
Timing Late Intake Manifold or Cylinder Head
Gasket Leaks
Muffler or Exhaust Pipe Clogged or Bent
Spark
Plugs Dirty or
Defective

Breaker
Point Gap Incorrect
Breaker
Points
Defective
Ignition
Coil
or Capacitor
Defective

Electrical
Connection Loose
Broken
Valve Spring

Broken
Piston Ring or Piston
Cylinder
Head Gasket
Defective

Distributor Cap Cracked

Low
Compression
Valves Not Seating Properly Piston Rings Seal Poorly
Valve
Spring Weak or Broken
Cylinder
Scored or Worn
Piston Clearance Too Great

Cylinder
Head Gasket Leaks

Burned
Valves and
Seats
Valves Stick or Are Too Loose in Guides
Valve
Timing Incorrect

Valve
Head and Seat Have Excessive Carbon
Engine Overheats

Valve
Spring Weak or Broken

Valve
Lifter Seized or Collapsed
Exhaust
System Clogged
Valves Sticking

Valve
Stem Warped

Valve
Stem Carbonized or Scored

Valve
Stem Clearance Insufficient in Guide

Valve
Spring Weak or Broken

Valve
Spring Distorted
Oil
Contaminated

Overheating
Cooling System Inoperative
Thermostat Inoperative Ignition Timing Incorrect

Valve
Timing Incorrect
Carbon
Accumulation Excessive

Fan
Belt Loose
Muffler or Exhaust Pipe Clogged or Bent

Oil
System Failure
Piston Rings Worn or Scored
Popping,
Spitting,
Detonation
Ignition Timing Incorrect

Carburetion
Improper

Carbon
Deposit
in Combustion
Chambers Excessive
Valves Not Seating Properly
Valve
Spring Broken
Spark
Plug Electrodes Burned
Water or Dirt in
Fuel
Fuel
Line
Clogged
Valve
Timing Incorrect

Excessive
Oil
Consumption
Piston Rings Stuck in Grooves, Weak,
Worn,
Broken, or Incorrectly Fitted

Crankshaft
Main Bearings or
Connecting Rod Bearings Have
Excessive Clearance
Gaskets or Oil Seals
Leak

Cylinder
Bores Worn, Scored,
Out-of-Round or Tapered
Pistons Have Too Great Clearance to Cylinder Bores
Connecting Rods Misaligned High Road Speed
High Temperature

Crankcase
Ventilation System Inoperative
Bearing Failure
Crankshaft
Bearing Journal Rough or Out-of-Round

Oil
Level Low
Oil
Leakage

Oil
Dirty
Oil
Pressure Low or Lacking
(Oil
Pump Failure)

Drilled
Passages
in Crankshaft or
Crankcase
Clogged

Oil
Screen Dirty
Connecting Rod Bent 105

'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
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

FUEL
SYSTEM

1-5/32

133S2

FIG.
E-23—FLOAT
LEVEL
ADJUSTMENT
l—Float
Arm 2—Float Scam

horn
to fuel bowl with attaching screws. Tighten screws evenly and securely.

Note:
Longest air horn attaching screw
goes
in top
of pump housing.

m.
Install
choke rod into choke lever and fast-idle

cam.
Install
fast-idle cam screw and tighten se­

curely.
See Fig. E-25 for proper installation,
n.
Insert accelerator pump rod through outer
hole

and
into throttle lever; fasten with retainer.
A33S3

FIG. E-24—FLOAT DROP ADJUSTMENT
1—Float Tang 2—Float Drop Gauge 3—Float
E-40.
External
Carburetor
Adjustment

All
adjustments on the carburetor, except for float
adjustments, are made externally. For float level

and
drop adjustments, see
steps
j and k of Par.

E-38,
above.

E-41.
Accelerator Pump Adjustment

Unthread
curb-idle speed adjustment screw and completely
close
throttle valves in bore. Place
pump
gauge
across top of carburetor air horn ring,
as shown, with 15^" [29,369 mm.] leg of
gauge
pointing downwards, towards top of pump rod.

Lower
edge
of
gauge
leg should just touch the top
of the pump rod. Bend the pump rod, as required, to obtain the proper setting. See Fig. E-26. ]
13354

FIG.
E-25—CHOKE LINKAGE—INSTALLED VIEW 1—
Choke
Lever

2—
Trip
Lever

3—
Choke
Rod
4—
Throttle
Stop Screw 5—
Pump
Rod

13355

FIG.
E-26—ACCELERATOR
PUMP
ADJUSTMENT 1—
Pump
Gauge 2—
Pump
Rod

3—
Throttle
Shaft — Closed Position
E-42.
Curb
Idle Speed and Mixture
Adjustments

Adjust
curb idle speed adjustment screw to obtain

engine
idle speed as specified in Par. E-79. See Fig.

E-15.

When
engine
is at normal operating temperatures,

adjust
idle mixture
needle
screws to obtain smooth­
est
engine
idle; readjust idle speed if necessary.

Note:
Engine run on or "dieseling" is a condition

in
which combustion continues to take place after
the normal ignition spark from the distributor has
been shut off by turning off the ignition switch. It 124

'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