1953 JEEP DJ water pump

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

Dl
Dl-65.
Rocker Arm Cover Cleaning
and Inspection

a.
Clean
both rocker arm covers with suitable
cleaning solvent and dry thoroughly.

b.
Inspect each rocker arm cover visually for

scratches,
bends, dents, and tears. Replace cover

if
unserviceable.

Dl-66.
Timing Chain
and
Sprocket Inspection

Inspect
the timing chain and both sprockets for
damage or excessive wear. Replace unserviceable
parts.

Dl-67.
Timing Chain Cover Cleaning and Inspection

a.
Clean
the timing chain cover with suitable clean­
ing solvent and dry with compressed air.

b.
Inspect the cover visually for breaks,
cracks,
and
other damage.
With
a straightedge, check cylinder
block, water pump, and oil pump faces for bends

and
distortion.

c.
Install
oil pump gears in oil pump cavity of
timing gear cover.
With
a straightedge and feeler
gauge,
check gear and clearance. Refer to Fig.

Dl-30.
Clearance
should be
between
.0023"
[0,0584

mm.] and .0058"
[0,1358
mm.]. If it is lower
than
.0018" [0,0457 mm.], inspect thrust surfaces
of cover which touch gears for wear.

d.
Replace the timing chain cover if unserviceable.
FIG.
Dl-30—CHECKING
OIL
PUMP
GEAR

END
CLEARANCE

1—
Feeler
Gauge
2—
Straight
Edge

3—
Pump
Body
4—
Pump
Gears
Dl-63.
Oil Pump Cleaning and
Inspection

a.
Clean
gears with suitable cleaning solvent and

dry
thoroughly. Inspect for wear, scoring, and other damage. Replace either or both gears if unservice­
able.

b.
Remove the oil pressure relief valve cap, spring

and
plunger. Refer to Fig. Dl-31. Oil filter bypass
valve plunger and spring are staked in place and should not be removed. 12719

FIG.
Dl-31—OIL
PUMP
PRESSURE
RELIEF
VALVE

1—
Valve
Cap
2—
Gasket

3—
Spring

4—Valve
5—
Oil
Pump
Cover
c.
Wash valve parts thoroughly. Inspect the relief
valve plunger for wear or scoring.
Check
the spring to see that it is not worn or collapsed. Replace any
relief
valve spring that is questionable. Thoroughly

clean
the screen staked in the cover.

d.
Insert the relief valve plunger into its bore in
the cover. The plunger should have no more clear­ ance than an easy slip fit. If there is any perceptible
sideways movement, the plunger and/or the cover should be replaced.
e.
Check
oil filter bypass valve plunger for
cracks,

nicks,
or warping. The plunger should be flat and free of nicks or scratches.
f.
Lubricate
and install pressure relief valve plung­
er
and spring in bore of oil pump cover.
Install

cap and gasket. Torque cap to 30 to 40 lb-ft. [4,1 a 5,5 kg-m.]. Do not over-tig1 n.

Note:
Pressure relief valve cap has no tapped
hole

for installation of oil pressure switch.

H1
-69.
Crankshaft Vibration
Damper
Inspection

Inspect
the crankshaft vibration damper for
cracked,
broken, distorted, or otherwise damaged
condition. If damaged, replace.

Dl-70.
Crankshaft Pulley Inspection

Inspect
the crankshaft pulley for damage or exces­
sive wear. Replace if visibly worn or damaged.

Dl-71.
ENGINE REASSEMBLY

The
engine
assembly procedure in the following
paragraphs
is given in the sequence to be followed
when the
engine
is being completely overhauled.
Individual
inspection,
repair,
and fitting operations
previously covered in detail are made throughout
the assembly procedure. The assembly procedure
does
not cover accessories. If a new cylinder block
fitted with pistons is used, many of the operations

will
not be required.

Mount
the cylinder block in an
engine
repair stand.
If
an
engine
stand is not available, perform the
following assembly operation in a manner designed to protect personnel against an accident, and the
engine
and its parts against damage. 95

Dl

DAUNTLESS
V-6
ENGINE
Note:
During
engine
reassembly, use Perfect Seal

Aerosol
Spray Sealer
Part
No.
994757
on all en­
gine
gaskets to ensure against vacuum, oil, gasoline

and
water leaks. Apply to head gaskets, valve covers, water pumps, oil pan gaskets, radiator and
heater
hose
connections, felt gaskets, gasoline and
oil
line connections, stud bolts, spark plug threads,

and
grease retainer washers. Refer to manufac­
turer's
instructions on container for proper appli­
cation procedure.

Dl-72.
Cylinder
Block
and Crankshaft
Rear
Oil Seals

Braided
fabric seals are pressed into
grooves
of
cylinder
block and
rear
main bearing cap, to
rear

of the oil collecting groove, to seal against oil leak­ age at the crankshaft. Refer to Fig. Dl-32.

FIG.
Dl-32—INSTALLING
CRANKSHAFT REAR
OIL
SEAL

1—Neoprene
Seal
2—Fabric
Seal

A
neoprene composition (stick) seal is installed in
grooves
in the sides of the
rear
main bearing cap
to seal against leakage in the joints
between
the
cap and cylinder block. The neoprene composition
expands in the presence of oil and heat.
This
seal
is undersize when newly installed. Refer to Fig.

Dl-32.

a.
The braided fabric seal can be installed in the

cylinder
block only when the crankshaft is re­ moved; however, the seal in the cap can be replaced
whenever the cap is removed. Remove oil seal and place new seal in groove, with both ends projecting
above parting surface of cap. Force seal into
groove

by rubbing down with hammer handle or smooth
stick
until seal projects above the
groove
not more

than
[1,59 mm.]. Cut ends off flush with
sur­

face of cap, using sharp knife or razor blade.
Lubricate
the seal with heavy
engine
oil just before
installation.

Caution:
The
engine
must be operated at slow
speed when first started after new braided seal
has been installed.
b. The neoprene composition seal is slightly longer

than
the
grooves
in the bearing cap. The seal must
not be cut to length. The seals are installed after the bearing cap is installed in the block and torqued
firmly
in place. Dip the neoprene seals in kerosene
approximately IV2 minutes, then install seals into
bearing cap grooves. The protruding ends of the seals are, again, squirted with kerosene, wiped off,

and
peaned over with a hammer to be sure of a
seal
at the upper parting line
between
the cap and

cylinder
block.

Dl-73.
Main
Bearing and Crankshaft
Installation

Refer
to Fig. Dl-6.

This
procedure assumes that crankshaft main bear­
ings have been inspected and proven satisfactory,

or
that new crankshaft main bearings of appropriate size have been selected. If necessary, check or select
main
bearings as described in Par. Dl-41 and
Pars.

Dl-42 and Dl-43.

a.
Install
four upper main bearing halves in
seats

of cylinder block so that prong of each bearing half
fits into corresponding notch of seat. Flanged thrust
bearing must be installed in the second seat from
front of engine.
Install
a new upper crankshaft
rear
oil seal in the cylinder block as described in

Par.
Dl-72.

Caution:
Upper main bearing halves have an oil groove, while lower halves are plain. They must
not be interchanged.
b. Apply
engine
oil to upper bearing surfaces.

Install
the crankshaft so that its four journals rest

in
the upper bearing halves.
c. Seat all four lower main bearing halves in cor­
responding bearing caps.
Install
a new lower
crank­

shaft
rear
oil seal and cylinder block
rear
oil seal
described in
Par.
Dl-72, a and b.
Lubricate
all lower

main
bearing surfaces with
engine
oil. Position bear­ ing caps to cylinder block and crankcase journals.

Install
two cap bolts,
loosely,
at each cap.

d.
It is necessary to align thrust surfaces of the
second main bearing whenever it has been removed

from
the engine. To do this, pry the crankshaft

back
and forth several times, throughout its entire end travel, with cap
bolts
of second main bearing
only finger tight.
e. Tighten alternate cap
bolts
of each main bearing

cap,
a little at a time, until they have been tight­ ened to 80 to 110 lb-ft. [11,1 a 15,2 kg-m.] torque.
D1-74. Crankshaft End Play Check

To
measure crankshaft end play, mount a dial
indicator
on the cylinder block and index its plung­

er
to either a front or
rear
face of one crankshaft
counterweight. Pry the crankshaft to one limit
of its end travel and adjust the dial indicator to
zero. Pry the crankshaft to its
opposite
end travel

limit
and
note
end play as indicated by the dial

indicator.
Crankshaft end play tolerances are .004"
to .008" [0,102 a
0,204
mm.]. If end play is too great, it can be corrected only by replacement of
the second main (thrust) bearing.

Dl-75.
Piston and Connecting Rod
Installation

This
procedure assumes that connecting rod bear­ ings have been inspected and proven satisfactory,

or
that new connecting rod bearings of appropriate 96

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

Dl
of packing are at top. Drive in a new shedder with

a
suitable punch. Stake the shedder in at least three places to secure it in position. Size the pack-
FIG.
Dl-39—INSTALLATION
OF
TIMING

CHAIN
AND
SPROCKET

1—
Camshaft
Sprocket 3—Timing
Chain

2—
Crankshaft
Sprocket 4—Timing
Marks

FIG.
Dl-40—FUEL
PUMP
ECCENTRIC
AND
DISTRIBUTOR
DRIVE GEAR
1—
Fuel
Pump
Eccentric
3—Camshaft
2—
Oil
Groove 4—Distributor Drive
Gear
ing by rotating a hammer handle, or similar smooth
tool, around it, as necessary, to obtain clearance
for the crankshaft vibration damper hub.

Dl-86.
Install
Timing
Chain
Cover

Note:
There
are five
bolts
which attach the timing

chain
cover directly to the cylinder block, and seven
bolts
which attach both the timing chain
cover and water pump to the cylinder block.

a.
If oil pump has not been removed from timing

chain
cover, remove fine slotted attaching screws,

oil
pump cover, gasket from timing chain cover. Completely pack the space around the oil pump gears with petroleum jelly.
There
must be no air
space left inside the pump. Secure oil pump cover

and
a new gasket to timing chain cover with five slotted attaching screws. Torque screws, alternately
and
evenly, 8 to 12 lb-ft [1,10 a 1,66 kg-m.].

Note:
Unless oil pump gears are packed with petro­
leum jelly, pump may not prime itself when
engine

is started.

b.
The gasket surfaces of the cylinder block and
timing chain cover must be smooth and clean. In­
stall
a new timing chain cover gasket and position

it
correctly on the cylinder block.

Note:
Two different timing chain cover gaskets
have been installed in production on V-6 engines.

At
any time the timing chain cover gasket is
replaced,
make sure the correct gasket is installed.

c.
Position timing chain cover to cylinder block.

Use
timing cover aligner and oil seal remover tool J-22248. Be certain that dowel pins
engage
dowel

pin
holes
before installing bolts.

d.
Lubricate
bolt threads before installation.
Install

the mounting
bolts
and torque 25 to 33 lb-ft. [3,5
a
4,6 kg-m.].

Note:
Some timing chain covers have two additional
bolts, one in each upper corner. If the timing chain
cover being installed on a crankcase with
these
two
holes
does
not have matching holes, the
holes

in
the crankcase must be plugged with two hex
socket screw plugs. The plug should be driven past
the face of the case to prevent interference with the timing chain cover. These
bolts
are not shown

in
Fig. Dl-41.

D1-87.
Install
Oil Pump

a.
Pack
•
oil pump gear pocket of timing chain
cover with petroleum jelly. Do not use chassis
lubricant.

b.
Install
gears so that petroleum jelly is forced
into every cavity of gear pocket and
between
the

teeth
of the gears.
Install
a new oil pump cover gasket.

Note:
Unless the pump is packed with petroleum

jelly,
it may not prime itself when the
engine
is

started.

c.
Mount oil pump cover on timing gear cover

with
five slotted attaching screws. Torque screws 101

Dl
DAUNTLESS
V-6
ENGINE

FIG.
Dl-41—WATER
PUMP
AND
TIMING CHAIN COVER BOLT LOCATION
Cover
Bolts

alternately and evenly 8 to 12 lb-ft. [1,10 a 1,66

kg-m.].

Dl-88.
Install
Crankshaft
Vibration
Damper

a.
Lubricate
the vibration damper hub
before
in­
stallation to prevent
damage
to the crankshaft
front oil seal during installation and when the

engine
is first started.
b.
Install
the vibration damper on the crankshaft.
Secure it with its attaching flat washer and screw.

Torque
the screw to a minimum of 140 lb-ft.
[19,35
kg-m.].

Dl-89.
Install
Crankshaft Pulley
Secure the crankshaft pulley to the crankshaft

vibration
damper with six screws. Torque screws 18 to 25 lb-ft. [2,5 a 3,4 kg-m.].

Dl-90.
Install
Oil
Level
Dipstick

Insert
oil level dipstick
into
the dipstick tube.

Dl-91.
Install
Oil
Pressure Sending Unit

Install
oil pressure sending unit in cylinder block.
Connect electrical wiring harness to unit.

Dl-92.
Install Starting Motor

Secure starting motor and
solenoid
assembly to
the flywheel housing and cylinder block with two attaching screws. Torque screw, which attaches this
assembly to the flywheel housing, 30 to 40 lb-ft. [4,1 a 5,5 kg-m.]. Torque screw, which attaches

bracket
to cylinder block, 10 to 12 lb-ft. [1,4 a 1,7 kg-m.].
Dl-93.
Install
Oil
Filter

Install
a new oil filter
element
at oil filter nipple,
at
left
side
of timing chain cover. Torque 10 to 15 lb-ft. [1,38 a 2,07 kg-m.].

D1-94. Install Water Pump
Be
certain that mating surfaces of the water pump

and
timing chain cover are clean.
Install
a new
gasket
on the pump flange. Secure the pump and
alternator adjustment bracket to the cover with
nine attaching bolts. Torque
bolts
6 to 8 lb-ft. [0,83 a 1,10 kg-m.]. Refer to Fig. Dl-41.

D1-9S.
Install
Cooling Fan
Secure the cooling fan, fan hub, and fan drive
pulley to the water pump shaft
flange
with four
attaching screws. Torque screws 17 to 23 lb-ft. [2,35 a 3,18 kg-m.].

Dl-96.
Install
Alternator
and Fan
Belt

Mount the alternator and bracket assembly on
right
cylinder head with two attaching screws.

Torque
screws 30 to 40 lb-ft. [4,1 a 5,5 kg-m.].

Fasten
the alternator
loosely
to its adjustment
bracket
with attaching flat washer and nut.
Install

the fan
belt
on its pulleys. Pivot the alternator
outward,
away from cylinder block, to apply fan

belt
tension. Adjust fan
belt
tension to 80 lb. [36,2 kg.];
tighten
alternator-to-adjustment bracket
nut to secure adjustment
setting.
Connect wiring
harness to alternator.

Dl-97.
Install
Fuel Pump

Install
two mounting
bolts
and new
gasket
on

flange
of fuel pump. Secure pump to timing chain cover with screws; torque screws 17 to 23 lb-ft. [2,35 a 3,8 kg-m.]. Connect
output
fuel line to
pump.

Dl-98.
Install Exhaust Manifold

Secure each of two exhaust manifolds to corre­
sponding cylinder head with five attaching screws,
and
one nut. Torque screws and nut 15 to 20 lb-ft. [2,07 a 2,8 kg-m.]. See Fig. Dl-42.

Dl-99.
Install Distributor

Insert
distributor drive gear
into
distributor mount-
FIG.
Dl-42—EXHAUST
MANIFOLD INSTALLATION

1—Torque
Bolts—15
to 20
lb-ft.
[2,07 a 2,8
kg-m.]

102

'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

FUEL
SYSTEM
Contents

SUBJECT
PAR.

GENERAL
E-1 Dash

FUEL
EVAPORATIVE EMISSION
?*^r
CONTROL SYSTEM
..E-2
Canister
.E-3 . Demand Valve E-4

Fuel
Tank.
.E-5
Inspection Test. E-8
Sealed Gas Cap. E-7

Servicing
System E-9
Vapor
Separator or Expansion
Tank
E-6

CARBURETOR
—
HURRICANE F4 ENGINE.
. .
......
..... ,. . .E-10 Accelerating Pump System.............. .E-19 Accelerating Pump Maintenance E-20

Carburetor
Reassembly
E-2
2

Carburetor
Disassembly E-21
Choke
System E-17
Dash
Pot Adjustment E-44

Fast
Idle Adjustment E-18
Float
Adjustment E-12
Float
System. E-ll
High-Speed System . .E-15
Idle
Adjustment .E-14

Low-Speed
System . E-13
Metering Rod Adjustment E-16

CARBURETOR
~r
DAUNTLESS V-6 ENGINE
.E-25
Accelerator Pump Adjustment E-41 Accelerator Pump System. . E-30

Air
Horn Body Assembly E-39
Air
Horn Body Removal and Disassembly.
E-33

Carburetor
Cleaning and Inspection E-36
Carburetor
Removal E-32
Choke
System E-31

Curb-Idle
Speed and Mixture Adjustment. .E-42

E-1. GENERAL
The
fuel system of the Jeep Universal vehicle,
whether equipped with a Hurricane F4 or Daunt­

less
V-6 Engine,
consists
of the fuel tank, fuel lines, fuel pump, carburetor and
air
cleaner.
Fig. E-1, E-2.
Vehicles equipped with a
Fuel
Evaporative
Emis­

sion Control System
also
include a
non-vent

pressure and vacuum
sensitive
gas cap, a liquid
expansion and vapor separator tank, a carbon filled vapor
storage
canister, and a vapor purge line. Service information pertaining to the
Fuel
Evap­

orative Emission Control System is outlined in

Par.
E-2 through
E-9.
Refer to Figs. E-3 and E-4.
The
most
important
attention
necessary to the fuel
system is to
keep
it clean and free from water. It should be periodically inspected for leaks.

CAUTION—Whenever
a vehicle is to be stored for

an
extended
period, the fuel system should be com­

pletely
drained, the
engine
started and allowed to
run
until the carburetor is emptied.
This
will
avoid
oxidization of the fuel, resulting in the formation of
SUBJECT
PAR.
Pot Adjustment .E-44

nal
Carburetor Adjustments.........E-40

Idle
Adjustment
.
E-43 System . . .E-26

Bowl
Body Assembly E-38

Fuel
Bowl Body Disassembly E-34

Idle
System E-27

Main
Metering System E-28
Power System . E-29
Throttle
Body Assembly .E-37

Throttle
Body Removal, and Disassembly. .E-35

FUEL
PUMP
—
HURRICANE F4 ENGINE.
E-45, 54, 60

Cleaning
and Inspection.............
.E-57,
63 Disassembly E-46, 56, 62
Installation E-59, 65
Reassembly
.E-47,
58, 64
Removal
E-55, 61

Testing.
E-49, 50, 51, 52, 53, 66

Vacuum
Pump E-48

FUEL
PUMP
—
DAUNTLESS V-6 ENGINE
E-67
Removal
E-68

AIR CLEANER
—
CARBURETOR
E-69
ACCELERATOR
LINKAGE
.E-70

FUEL
TANK
AND
LINES
E-71
Float
Unit . .E-76
Fuel
Lines E-77
Fuel
Tank
. . .E-72

Fuel
Tank
Cap E-75

Fuel
Tank
Installation. E-74
Fuel
Tank
Removal E-73

SERVICE
DIAGNOSIS
E-78

SPECIFICATIONS.
E-79
gum in the units of the fuel system. Gum formation
is similar to hard varnish and may cause the fuel
pump valves or the carburetor
float
valve to be­
come
stuck or the filter screen blocked. Acetone or commercial fuel system cleaners
will
dissolve

gum formation. In
extreme
cases
it
will
be necessary
to dissassemble and clean the fuel system. In
most

cases, however, a
good
commercial fuel system sol­
vent
used in accordance with the manufacturer's
instructions or one pint [0,6 ltr.] of
acetone
placed
in
the fuel tank with
about
one gallon [4,5 ltr.]
of
gasoline
will
dissolve
any
deposits
as it
passes

through the system with the
gasoline.

E-2.
FUEL
EVAPORATIVE EMISSION CONTROL SYSTEM

Description and Operation

•
Refer to Figs. E-3 and E-4.

The
Fuel
Evaporative Emission Control System
is
designed
to reduce fuel vapor emission that 109

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
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