Stromberg WW Carburetor Manual - Buick

Frame 5:
The
new
typeStromb
. erg Carburetor
.
Idraft
' easi
.
ow over-all
d ly. recognized
by isit a 2-b
If arrel, downcarburetors Seslgn. As with previ s 0 set bowl and
th
' trombe •
ous Bui k
rg s dual constr . c 2-barrel
e advantages of
pact
uni
two carb uretors i n uction
mrovi
et umt.
provides
one single
com-
Frame 6:
asrc carAs
usual ' w ithi10th '
buretor
circuits.
e single unit are five b .
FLOAT CIRCUIT
CHOKE CIRCUIT
PUMP CIRCUIT
LOW-SPEED CIRCUIT
HIGH.SPEED CIRCUIT
4
,:
Frame 7:
•
FLOAT AND
LEVER ASSEMBLY
I
During operation, air
is supplied to the float
chamber through the
external bowl vent
located in the air horn.
Fuel enters the float
chamber directly
through the side of the
main body. Because
fuel is supplied to both
barrels from one float
chamber, a single float
and lever assembl y
actuates a needle
valve.
ACCELERATING SYSTEM
Frame 8:
In the accelerating system, th e pump
discharge nozzle in each barrel is
supplied with fuel from the pump
piston located in the float chamber.
PUMP
DISCHARGE
NOZZLE
PUMP
PISTON
POWER SYSTEM
Frame 9:
The power system for
both barrels is controlled by the vacuum
power piston. Except
for the items mentioned, each barrel
forms a complete carburetor system.
5
Fra me 10:
~ IDLE SYSTEM
ADJUSTABLE WITH
~
~
~
MAIN METERI:EEDLE VALVE '
ACCELERATIN G SYSTEM
This means that
each barrel contains an idl
twith ad'justable needl
em,
an
accelerari
' met e. system
d
anng p e valve, a rna rn
an throttle val
ump, discharge
enng sysve. Th h
nozzl
ace mounted m
' line
,
eont rottle val ves of both
e, venturi
b arrels
one shaft.
DISCHARGE G PUMP
VENTURI
NOZZLE
> THROTTLE VALVE
Frame 12:
One new f eature is th
automatic choke h
~ location of the
of the alurnin
ouslOg, now a pa
. h
urn th
rt
t rottle bod
. rattle bod T'
stall'
y design hel
y, hIS
Ing caused b
ps overcome
y carbureto r ICIng.
..
Frame 13 :
The the rrnostatic sprin
b
y removing the h kg
and gasket. Inside
c 0th e
can be found . . .
e
6
can be located
h ousmg
.
cover
housing itself
Frame 14:
. . . the fast idle lever, the
choke positioning lever, the
pickup lever . . .
Frame 15:
. . . the fast idle cam and the choke positioning
spring. The absence of a choke piston means the
choke valve is positioned mechanically instead of
by a vacuum piston.
Frame 16:
NOTE: A left-hand threaded nut holds the retaining lever
to the end of the throttle shaft. Its head is colored
black as a reminder.
LEFT.HAND
THREADED NUT
Frame 17:
Another new feature is found in the choke valve.
From the shaft up, this valve is bent six degrees
forward to keep the choke valve wide open after
operating temperature is reached.
7
Frame 18:
Another new feature is the cone-shaped
ball check seat in the accelerator
plunger well. This permits the ball
check to be merely dropped in for
proper installation.
Frame 19:
A WORD OF CAUTION : During a
bench overhaul, the idle tubes will
fall out if the carburetor is turned upside down with the air horn removed.
Frame 20:
By turning the carburetor upside down,
Stromberg's three-hole
idle system can be seen.
The lower discharge
idle hole in each barrel
has an idle tube projecting into the carburetor
bore to improve lowspeed operation. All idle
channels in the main
body are surrounded by
fuel to keep them cool.
This reduces percolation.
8
Frame 21:
A final
o pnew fo
eature is th
ich
ermus th e spe Cia I moun
wh
haust heated intak
e transfer of h eat fronng gasket
h
t rottle b o d y Th e manifold to the mI t e exh
carburetor
.
IS feature p
.
a urninurn
fl
perfor
rovides '
ange gasket ' mance. NOTE' Thi Improved
C b
IS used
,IS m
ar uretor I d
only with hi
ounnng
found in rh toes not have exh t IS Stromberg
e Ca
aust g
h
mounted on the j rter gasket, and ' as oles as
e Intake manifold
It should be
as shown,
0
0
0
T (ALUMINUM)
HROTTLE BODY
0
INTAKE
MANIFOLD
0
Frame 25:
Correct f1 oat level d i
proper level f
a justrnent is '
Srrornbera' 0 fuel in the float
important in m '
thi:'~taining
hold the: s 2-hareel model rem howl. To check
the
level, usinoat arm tang against ove the air horn and a justment in
float
G:Uge J-5475 as
and
Then,
J st contact rh h
thisofposit'
theoffloat
e ottorn' In
edge
th IOn the top
the
e gauge.
shou~
sh:~nfloat n~edle c:::~et,
9
Frame 26:
Should adjustment be necessary, bend
the float arm tang, making sure the
float is positioned so as not to rub the
walls of the bowl. As this is the only
adjustment requiring the removal of
the air horn and gasket, make sure the
idle tubes and accelerator pump ball
check are in place. Then replace the
air horn and gasket.
Frame 27:
Correct plunger stroke is necessary
to assure delivery of the proper
amount of extra fuel when it is demanded. To make this adjustment,
install the accelerator pump rod with
the lower end in the medium stroke
or middle hole. Next, install new
cotter pins in the pump plunger and
pump rod.
Frame 28:
To make adjustment
possible remove the
throttle stop screw
and spring. Set the
spring aside and reinstall the screw,
turning it in until it
just contacts the
throttle lever, making
certain the throttle
is held closed.
10
Frame 29:
Measuring vertically from the air
horn casting to the top of the pump
plunger rod, bend the pump arm
as required, using Tool J-4552, to
obtain the specified measurement.
Then move throttle wide open to
make sure pump arm clears air horn
.casting.
START-AID
ADJUSTMENT
Frame 30:
To check for proper start-aid adjustment, hold the recommended drill
between the upper edge of the choke
valve and the air horn as shown.
Then by operating the throttle lever,
the start-aid should just clear the
choke unloader plate tang.
Frame 31:
If adjustment is
necessary, use Tool
J-5197 to bend the
unloader rod as
shown. Proper startaid adjustment is important. As you know,
it is an exclusive
Buick feature designed to prevent the
operator from unintentional choke unloading during initial
cold weather starts.
11
,DRILL
Frame 32:
The first step in making the choke
unloader adjustment is to open the
throttle valves fully so that the unloader arm on the throttle lever
kicks the choke valve partially open.
Next, gauge the opening by sliding
the recommended drill between the
upper edge of the choke valve and
the wall of the air horn.
Frame 33:
Should adjustment be necessary,
bend the un loader arm on the
throttle lever as shown. A properly
adjusted choke unloader provides a
means of clearing a flooded engine.
This feature is most needed when
the engine is partially warmed up.
Frame 35:
Removing the choke
housing cover and gasket permits us to identify the fast idle cam
and choke positioning
spring as well as the
thermostatic spring
mounted on the choke
housing cover.
12
Frame 36:
When the throttle is opened far
enough to engage the starter switch
during starting, the choke positioningspring has no effect on the choke
valve position.
CHOKE
POSITIONING
SPRING
Frame 37:
After the engine has started however, and the throttle is released,
the choke positioning spring engages the choke positioning lever
and overcomes any thermostatic
spring tension. This causes the choke
valve to partially open.
Frame 38:
With the throttle open,
the choke positioning
spring is disengaged
from the choke positioning lever as shown.
Then for most throttle
positions, the thermostatic spring controls
the choke valve and the
fast idle cam during the
warm-up period.
13
Fra me 39:
The fast idle cam and the fast idle
lever operate together to provide
enough throttle opening to prevent
stalling during the warm-up period.
Frame 40:
Begin the fast idle adjustment by
screwing the throttle stop screw in
5 turns from the fully closed throttle
position.
Fra me 41:
14
Closing the choke valve
will rotate the fast idle
cam so that the third
highest step is just opposite the fast idle lever
as shown on the left.
Then using the recommended drill, check the
clearance between the
fast idle lever tang and
the third step on the
cam. When adjustment
is necessary use Tool
J-5197 to bend the fast
idle lever as shown on
the right.
Frame 42:
The choke spring pickup lever adjustment is made by turning the
throttle stop screw in 2 additional
turns. This makes a total of 7 turns
in from a fully closed throttle position.
Frame 43:
At this throttle opening, the choke
positioning spring should just contact the pickup lever tang. If necessary, use needle-nose pliers to bend
the pickup lever tang. Back out the
throttle stop screw to close the
throttle valves .
Frame 44:
To check the fast idle
cam setting, open the
throttle so that the fast
idle cam is free to rotate. Then, holding the
choke valve closed, close
the throttle until the fast
idle lever comes to rest
on the cam. The lever
should rest in the corner
formed b y the third
highest step and the cam
end lug with not more
than .020" clearance.
15
Frame 45:
If the clearance is not within limits,
adjust by bending the choke rod
with Tool J-5197.
Frame 46:
To make the choke positioning lever
adjustm ent , o p e n the throttle
slightly. Then rotate the positioning
lever until the positioning tang contacts the positioning spring.
Frame 47:
In this position, the recommended drill should
just pass between the
upper edge of the choke
valve and the air horn
wall as shown on the
left. If adjustment is
required, bend the tang
on the choke positioning
lever, as shown on the
right.
16
Frame 48:
To make the thermostatic spring
adjustment, install the gasket, cover,
retainers and screws, with the cover
index mark down. Rotate the cover
counterclockwise until the cover
mark aligns with the scribed mark
on the housing. Tighten the retainer
screws securely.
Frame 49:
To make the initial idle speed adjustment, remove the throttle stop
screw and reinstall the stop screw
spring. Then, turn the screw in until
it just contacts the closed throttle
lever, plus one additional turn.
Frame 50:
To make the initial idle
mixture adjustment ,
turn in the idle mixture
needles until they contact the needle seats
lightly. Back out each
needle 1 % turns.
17
Frame 51:
After hooking up a tachometer and
vacuum gauge, start the engine and
allow it to reach normal operating
temperature. Then adjust the
throttle stop screw to obtain an engine speed of 450 r.p.m. in neutral.
Should it be necessary to adjust the
starter switch, use the procedure
outlined in your current Buick Shop
Manual.
Frame 52:
Turn the mixture adjusting needles
until the highest steady vacuum
gauge reading is obtained.
Frame 53:
Remember, road-testing
the car for proper carburetor operation should
be the final step in carburetor adjustments. It's
the sure way of knowing that yours is a job
well-done.
18
STROMBERG WW Adiustment Procedure
FLOAT LEVEL ADJUSTMENT
•
Hold floa t a rm ta ng against float
needle and check floa t level, using
Gauge J-5 475 as sho w n. Top of float
should just co ntact t he bottom edge
of gauge. To adjust, bend float arm
ta ng.
PLUNGER STROKE ADJUSTMENT
Lower end of accelerator p u mp rod
s h o u l d be in mid dle or medium
st ro ke hole of the throttle arm. Remo ve and set aside throttle stop
screw spring. Reinstall stop screw , . .
turning it in until it jus t co ntacts If
throttle lever wi t h t he t hrottle closed.
Specified gap between top of be nt
end of pump p lu nger rod and top
of air horn casting should be Ys"
measured verticall y. Adju st by bend ing pump rod using Tool J-4552.
START AID ADJUSTMENT
Posi tion choke va lve partly open
with the reco mm ended d rill betwee n
... edge of choke valve and wall of air
, . horn. End of start-aid sp ring shou ld
just clear choke unl oader plate tang
w hen t hrottle is opened . To adjust,
be nd unloader r od wi t h Tool J-5l97
as sh ow n .
CHOKE UNLOADER ADJUSTMENT
Open thro ttle wide so that u nloade r
arm kicks cho ke valve partly open.
Gauge the opening bet wee n edge of
choke valve a nd wall of air horn
wi th t he recomme nde d drill. To adjust, be nd the u nloader arm on
t h rot tl e lever as sh ow n.
..
If
FAST IDLE SPEED ADJUSTMENT
From full y closed position, turn
throttle stop screw in 5 turns. Close
... choke valve to pos ition third hig hest
, . step of fas t id le cam opposite fast
id le lever as shown on t he left. Check
clearance between fast id le lever
ta ng and third step of cam using the
recommended drill. Adjust by be nd ing fast idle lever as show n on right,
usi ng Tool J-5l97.
CHOKE SPRING PICKUP LEVER
ADJUSTMENT
Tu rn in throttle Sto p screw 2 additio nal turns, a total of 7 from full
closed throttle pos it ion . At this
throttle position, the choke positioning spring sho uld just contact t he
pickup lever ta ng . Adj u st by be ndi ng
pickup lever tang using need le-nose
pliers. When adj ustment is complete,
back out throttle stop screw to clo se
th ro ttl e valves.
..
If
FAST IDLE CAM ADJUSTMENT
Open th ro ttle sli g htly to clear fas t
idle cam. H o ld choke va lve clos ed
... an d dose throttle. Clearance between
, . t hi rd highest step of cam and fast
idle lever sho uld be betwee n 0 " and
.0 20". To adj ust, bend choke rod
usi ng Tool J- 5 l 9 7.
CHOKE POSITIONING LEVER
ADJUSTMENT
Open t hrottle slightly to clea r fas t
idle cam. Ro ta te p ositioning lever
until positioning tan g just contacts . .
positioni ng spri ng . I n this p osit ion, If
th e recom me nde d d rill should just
pass betw een edge of cho ke valv e
a nd ai r ho rn wa ll as shown o n left.
To adj ust bend ta ng on cho ke po sitio ning lever as shown on ri ght.
19
Thermostatic Spring (Chok e) Adjustment, Install choke cover
with index mark downward. Rotate cover counterclockwise
until index mark aligns with scribed mark on choke housing.
Tighten retainer screws securely.
SPECIFICATIONS
NOTE: The adjustments must be made in the proper sequence, as some adjustments affect succeeding adjustments.
ADJUSTMENT
20
SETTING
TOOL NO.
Float Level
3 /16/1 below edge of bowl
J-5475
Pump Plunger Stroke
7 /8/1 at plunger rod
J-4552
Start-Aid
No. 53 drill
J-5197
Choke Unloader
No. 27 drill
Pliers
Fast Idle Speed
5 turns
Choke Spring Pickup Lever
7 turns in
Fast Idle Cam
o to .020/1
Choke Positioning Lever
No.5 drill
Choke
Align index marks
Initial Idle Mixture
1% turns out
Initial Idle Speed
1 turn in
In.
No. 48 drill
J-5197
Pliers
(J-1388)
J-5197
Pliers
StrombergWWRebuildProcedure
Disassembly
1. Because the throttle valves extend below the flange when open, use a mounting fixture or
four bolts to support the carburetor and to prevent damage to the valves. Remove the cotter
key (A) and the pump rod (B). Remove the hairpin clip (C), and the left-hand thread screw
(D) to take off the pump fulcrum lever (E). Remove the hairpin clips (F) and the fast idle rod
(G). Take out the six air horn attaching screws (H), and lift off the air horn.
2. Remove the vacuum power piston by using a block of wood as a fulcrum and an open-end
wrench as a lever.
3. Remove the cotter pin (I) from the vacuum choke piston lever and apply pressure against
the lever to force the choke vacuum piston expansion plug from the end of the bore. The
black arrow points to the model number of the carburetor which is required when ordering
parts.
4. Remove the choke vacuum piston from its bore.
5. To disassemble the main body, remove the accelerating pump spring (J) and the pump
piston (K). Hold your hand over the bowl while you pry out the spring clip (L) which holds
the float fulcrum pin (M). Lift out the float (N) and the pin. Unscrew the float inlet needle and
seat assembly (0). Lift out the two idle tubes (P). Remove the pump discharge nozzle (Q) and
the power jet (R). Invert the carburetor, holding your hand under it to catch the two
accelerating pump ball checks.
6. Take off the throttle body flange by removing the four retaining screws (S) and remove the
idle needle valves and springs (T).
7. Remove the main metering jet plug, the gasket, and the main metering jet. Pull the main
discharge jet with tool No. 73608. Repeat for the other side of the carburetor.
CleaningandInspecting Clean all parts in carburetor cleaner. Follow with a solvent bath and blow dry. The
accelerating plunger which contains leather should be cleaned only in mild solvent such as
kerosene or light oil — never in a carburetor cleaner. Blow compressed air through all
passageways and jets to make sure that they are open.
Move the throttle shaft back and forth to check for wear. If the shaft appears to be excessively
loose throttle shaft bushings may be installed, but this procedure requires special tools; expert
assistance is recommended. Inspect the main body, air horn, and throttle body gasket surfaces
for cracks and burrs which might cause leaking.
Shake the float to check for a leak. Replace or repair it if it has liquid in it. Leaky floats can
often be repaired by re-soldering.
The Stromberg power jet frequently leaks.
Test it by sucking on it and alternately depressing the tip of the rod with your tongue.
The main metering jet and the nozzle.
The black arrow points to the air bleed hole which is sometimes squeezed egg-shaped by
applying too much pressure on the main metering jet wrench.
Check the idle adjusting needles; replace any that has a groove in its tapered section.
Check the power jet by sucking on it. Use your tongue to open and close the jet. Replace it if
it leaks.
Check the air bleed hole in the main delivery jet (black arrow) which is frequently squeezed
egg-shaped by applying too much pressure when tightening the main metering jet. Replace
the nozzle if the bleed hole is defaced.
Assembly
8. Place the throttle body flange on the main body using a new gasket. Align the holes and
install the four retaining screws. Replace the main discharge jets and main metering jets.
Align each discharge jet carefully with the square recess of the hole and push it in place with
a wooden stick to prevent damaging the shoulder. Avoid using too much pressure when
tightening the main metering jets; otherwise, you will squeeze the air bleed holes out of
shape. Replace the plugs using new gaskets. Insert the smaller of the two check balls into the
center passageway and replace the discharge nozzle.
9. Replace the idle tubes (interchangeable), the float needle valve and seat assembly, and the
float. Press on the loop of the retaining clip to
lock the fulcrum pin in place. Install the
smaller ball check into its hole in the pump
well.
10. To make the float level adjustment, use the specified gauge and bend the float lever at the
float end as required.
11. To assemble the air horn, insert the vacuum piston into its bore. Attach the link to the
choke lever and check for free operation. Secure it with a cotter pin. Place a new expansion
plug in the housing and stake it lightly to keep it in place. Install the vacuum power piston and
stake it lightly. Assemble the pump spring and washer over the end of the pump rod and push
the assembly through the hole in the air horn. Assemble the end of the rod to the pump
fulcrum lever using a hairpin retainer. Secure the lever to the casting with the left-hand thread
screw.
12. Place the air horn gasket in position and guide the pump piston into the pump cylinder.
Make certain that the leather is not creased. Install and tighten the air horn attaching screws.
Replace the fast idle rod. Install the pump rod, connecting it to the center hole of the throttle
lever.
BENCHADJUSTMENTS
13. To make the fast idle speed and cam position setting, turn out the idle speed adjusting
screw until the throttle valves seat in the bores, With the fast idle adjusting screw against the
shoulder of the last step, and the throttle valves fully closed, bend the fast idle rod as required
so
the
specified
gauge
can
be
withdrawn
with
a
slight
drag.
14. To make the unloader adjustment, apply a light closing pressure to the choke valve and
then open the throttle valves wide. The choke valve should open just enough to enable you to
insert the specified gauge between the valve and the wall of the air horn. Bend the ear of the
throttle lever as required.
15. To make the vacuum kick setting, insert a bent paper clip (0.040") between the rear of the
vacuum piston and the shoulder of the bore to keep the piston from fully returning. Close the
choke valve to bring the rear end of the choke piston against the wire gauge. Use the specified
gauge to measure the distance between the edge of the choke valve and the wall of the air
horn. Bend the piston lever ear as required.
16. To adjust the accelerating pump travel setting, hold the choke valve wide open and move
the throttle lever from its fully closed to its wide-open position. Measure the distance "J" and
bend the pump rod as required.