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MARVEL
CARBURETER
AND
HEAT CONTROL


AS USED ON
SERIES 691 NASH SIXES


BOOKLET
S


MARVEL CARBURETER CO.
FLINT, MICHIGAN
U.S.A.




MODEL "S" CARBURETER

Used on Series 691 Nash Sixes


The carbureter measures the fuel charges for the engine and
automatically mixes them with the proper amount of air to form a highly
combustible gas. The Marvel Model "S" Carbureter is of the automatic air
valve, heat controlled type. Its outstanding advantages are:

1. Simplicity of construction and operation.

2. Quick starting in any weather.

3. Automatically controlled heat application to ensure complete
vaporization of fuels.

4. Economy in fuel consumption.

5. Ease of adjustment to meet varied driving and climatic conditions.


CONSTRUCTION

The construction embodies a main body or mixing chamber and a
conventional float chamber bowl with fuel strainer attached at point of
entrance of fuel to bowl. Within the mixing chamber are two nozzles
which proportion the amount of gasoline used in the mixture. One of
these nozzles, called the "low speed," is regulated by the gasoline
adjustment screw at bottom of carbureter and the other, called the "high
speed," is controlled by the automatic air valve. An air screw is
provided which regulates the pressure of the air valve spring enclosed
therein. Within this screw is also enclosed a plunger connected by a
link to the air valve. The function of this plunger is to provide a
resistance in addition to that of the air valve spring to assist in
acceleration. This arrangement of plunger and air valve screw is termed
the dash pot.

A further control of the high speed jet is provided by the fuel metering
valve operated by the carbureter throttle. This valve provides the
maximum fuel feed to the "high speed" nozzle when the throttle is fully
opened for high speeds and for quick "pick up." During the ordinary
driving ranges this valve controls the amount of fuel being used, thus
providing all the economy possible. This valve is entirely automatic and
requires no adjustment.

The passage-way from the mixing chamber to the intake manifold is
controlled by a butterfly valve which is called the throttle-valve and
is connected to the throttle-lever on the steering wheel as well as to
the foot accelerator, its position determining the amount of gas and air
or mixture being fed the engine.


STARTING

A choke button is provided on the instrument board to assist in
starting. Pulling out this button closes a butterfly choker valve (see
cut) in the air intake passage of carbureter which restricts the air
opening of the carbureter, and consequently produces a richer mixture.

To start engine, pull out choke button all the way. Advance spark lever
about half way and throttle lever about one-quarter way and depress
starter pedal.

As soon as motor fires when starting, this control should be released
part way, otherwise too much fuel will be drawn from carbureter, causing
flooding of the motor and failure of the latter to continue to promptly
fire. After starting, motor should be allowed to run "part choke" as
stated for a few minutes while warming up, then the choker control
should be fully released, or pushed in completely on the instrument
board, and engine allowed to run normally for sometime until water in
cylinder jackets is thoroughly warmed up before starting to make final
carbureter adjustments.


HEAT CONTROL--STOVE

In the colder seasons warm air is fed to air intake of carbureter
through the warm air elbow "F" (see cut). This elbow connects the
carbureter with the warm air stove, which is a casting surrounding the
two exhaust heat tubes which supply exhaust heat to the carbureter
jackets as described below.

The amount of heat required for proper carburation depends on the
temperature of the outside air. The first means of control is in the
warm air stove just described, which should be connected to the
carbureter furnishing warm air to carbureter air intake in all seasons
of the year when the outside air temperature is below 50° F., whenever
the outside air temperature runs above this point cold air should be
furnished to carbureter air intake. This can be done by loosening the
wing nut holding the warm air elbow "F" on the stove and also loosening
the set screw holding this elbow in the air intake of carbureter, after
which slide elbow out of air intake and revolve it--180 degrees about an
horizontal axis and re-insert in carbureter air intake and lock in place
with set screw. The opening in the elbow now is turned down away from
the stove and draws in only cold air.

The above procedure, it must be understood, will vary somewhat due to
differences in locality, altitude and fuels used, but it should be borne
in mind that the best economy can be had with cold air passing to the
carbureter, and the stove should not be connected until the acceleration
and performance of the job requires the use of warm air for the best
results.

The adjustment of the carbureter should be made per the above
description of the stove, as the latter is used for meeting weather
conditions and should be set as described.


HEAT CONTROL--CARBURETER JACKETS

The carbureter and manifolds have been designed to utilize the exhaust
gases of the engine to insure complete vaporization and a consequent
minimum consumption of fuel. This is accomplished by surrounding the
upper portion of the mixing chamber with a large heat jacket provided
with an inlet and an outlet opening and connected by means of tubes to
an exhaust manifold valve body in the exhaust pipe of the engine; this
valve body, housing a large valve called the main-exhaust-heat-valve
("C" in cut) within the body itself, the return or outlet tube from the
carbureter heat jacket entering the valve-body in the lower portion
below the main-exhaust-heat-valve.

The main-exhaust-heat-valve "C" is connected by means of a lever and
long connecting rod to the throttle lever of the carbureter so that when
the throttle valve is operated the main-exhaust-valve is operated
simultaneously with it.

The purpose of the carbureter heat jacket and valve in exhaust line with
connections described, is to provide means for utilizing the heat of the
exhaust gases of the motor for vaporization of the fuel supplied the
engine by the carbureter and to do so automatically. The automatic
feature of same is accomplished by setting the Main-Exhaust-Heat-Valve
"C" by means of the long connecting rod, in closed position with the
closed or idling position of the throttle valve, thus providing for and
causing all of the exhaust gases of the engine to pass through the heat
jacket of the carbureter when engine is idling and to regulate the
volume of this heat as throttle is opened by automatically opening the
Main-Exhaust-Heat-Valve, thus allowing the increasing volume of the
exhaust gases to pass on out through the main exhaust pipe without being
deflected and by-passed to the carbureter heat-jacket as the motor speed
increases.

[Illustration: HEAT SETTING No. 1]

By referring to the cut shown (See Page 5) and noting "Heat Setting No.
1," it will be noted that valve "C" in main exhaust line is fully closed
with the closed or idling position of the throttle valve. This
adjustment is accomplished by having long connecting rod "R" from valve
"C" Lever set in "Hole No. 1," in Throttle Lever "L," being sure that
when throttle valve is standing in fully closed or idling position that
valve "C" is also in closed position, proving out the latter feature by
loosening connection of valve "C" lever holding long connecting rod;
holding Throttle Lever "L" in closed or idling position and bringing up
valve "C" lever on connecting rod "R" as far as it will go to the right
toward the carbureter and tightening its connection on the connecting
rod in that position. After having made the adjustment as just
described, it is assured that "Heat Setting No. 1" has been properly
made and that all of the heat possible from the exhaust has been
secured.

This "Heat Setting No. 1," provides as stated, for the most exhaust heat
obtainable and should be used during the entire year, except in
extremely hot seasons or hot climates or when high-test gasoline is
being used in engine and even then unless engine is losing power due to
excessive heat.

If loss of power or mileage due to too much heat is experienced, first
be sure that it is not due to driving on hot-air instead of cold-air.
After making this observation, if there is still too much heat, refer to
cut (See Page 7) describing "Heat Setting No. 2." It will be noted that
connecting rod "R" from valve "C" is removed from "Hole No. 1," in
Throttle Lever "L" and placed in "Hole No. 2," in Throttle Lever. This
change is all that is necessary in order to reduce the amount of heat
applied to carbureter. In "Heat Setting No. 2," when the throttle is in
closed or idling position, valve "C" is quite aways off its seat. This
adjustment provides for a great deal less heat than is provided by "Heat
Setting No. 1" and is all that is required in the reduction of the
volume of heat together with driving on "Cold" air for the
main-air-supply, in the warmest weather or hottest climates.

[Illustration: HEAT SETTING No. 2]


NOTE--After original position of valve "C" is made as described in "Heat
Setting No. 1" do not again readjust valve "C" on connecting rod but
when changing from "Heat Setting No. 1" to "Heat Setting No. 2," merely
change position of long connecting rod from "Hole No. 1" to "Hole No. 2"
in throttle lever.


ADJUSTMENT

No change should be made in the carbureter adjustments until after an
inspection has been made to determine if the trouble is in some other
unit. It should be noted that the gasoline lines are clear, that there
is gasoline in the vacuum tank, that there are no leaks at connections
between carbureter and engine, that the ignition system is in proper
condition, and that there is even compression in all cylinders.

If it is necessary to test adjustment or to make a readjustment proceed
as follows:

Set air screw so that the end is flush with the end of ratchet set
spring. Loosen packing nut on needle adjustment. Turn gasoline
adjustment to the right very carefully so as not to injure the needle
point, until the valve is closed gently against its seat. Then turn to
left approximately one complete turn which will bring notch in the disc
handle directly below the guide post above it. Tighten packing nut to
hold needle firmly as set.

The notch in disc handle of needle is put in handle after the needle has
been carefully calibrated by a flow-meter at the factory, therefore the
notch in handle should register with guide post above it. This setting
of needle valve is absolutely essential to get the best results. The
object in directing that needle be first turned to the right until
closed is to insure against two or more turns open, as from closed
position to notch (usually about one turn) is the normal setting. This
being true it is not necessary to turn needle in to the right firmly but
merely far enough to be sure that when turning back to the left, to the
notch registering with guide post, that the needle is not more than once
around or one turn from its seat.

Set stove heat and damper heat as previously instructed above. Pull out
choker to closed position and start engine in usual manner. As soon as
engine has fired release choker three-fourths of way in. Run until
engine has warmed up then push choker all the way in, remembering to
never use choker longer than necessary, as when not needed it has a
tendency to foul up engine and ruin the lubricating oil in the crank
case.

Next, set air screw for good idle by either turning to the right a
little or backing out to the left as the needs of the engine require,
remembering that first of all, the needle must be set as described. With
the needle so set and the engine warmed up, the adjustment of the air
screw for proper idling is easily accomplished by using a little care.
If the air screw is turned in too tight, the motor will roll. If the air
screw is not tight enough, the motor will hesitate and perhaps stop
entirely. To make a nice clean adjustment for idle, first having set
needle as described, turn air screw in quarter of a turn at a time until
engine, does roll; then turn back to the left until engine hesitates,
indicating that mixture has too much air and is too lean; next turn air
screw in to the right three or four notches at a time until engine runs
smoothly. This accomplished (and it is very easy to do by proceeding as
directed above) the proper adjustment for the entire range of the engine
will have been attained, thus insuring the best economy and power.


MODEL "S" MARVEL CARBURETER

[Illustration: STANDARD EQUIPMENT 1923-24 Series 691 Nash Sixes]


If the engine idles too fast with throttle closed, the latter may be
adjusted by means of the throttle lever adjusting screw.


RICH MIXTURE

An over-rich mixture will cause the engine speed to fluctuate through
more or less regular periods from high to low speeds; the engine will
seem to be mis-firing and there will be noticeable a strong odor, as
well as, usually, a heavy black smoke from the exhaust.


LEAN MIXTURE

The best adjustment is obtained with the fuel and air valves set as
described. It must be remembered that too lean a mixture as well as an
over rich mixture causes over-heating and loss of power and is not as
economical as an adjustment which provides just the proper proportion of
gasoline and air.


CAUTION

It must be remembered that the low speed needle has been carefully
calibrated to notch in disc handle and guide post above it, at the
factory and that in making an adjustment that the needle must be so set
and the rest of the adjusting done with the air screw as described,
never varying from described needle setting unless in extreme cold
weather, when a little more gas may be carried, or turning off a little
when casing head gas is used in hot weather.


MARVEL CARBURETER MODEL "S"

[Illustration: Nash Series 691 Sixes Parts Price List]

Part No.            Name               Price

10-80      Carbureter Body            $ 6.00
10-580     Carbureter Assembly         22.00
11-537     Insert Assembly              7.00
12-77      Accelerator Lever             .40
12-78      Throttle Lever                .40
14-2       Throttle Fly                  .25
15-5       10×24×1/2 Insert Lock Screw   .05
15-6       Bowl Support Screw            .05
15-14      Ratchet Spring Screw          .05
15-15      Bowl Cover Screw              .05
15-23      Throttle and Choker Fly
             Screws                      .05
15-28      Throttle Stop Adjusting
             Screw                       .05
15-29      6-32×1/4" French Head Screw   .05
15-32      Pilot Set Screw               .05
15-43      Square Head Set Screw         .05
16-5       Bowl Cover Gasket             .05
16-14      Strainer Gasket (fibre)       .05
16-16      Strainer Gasket (Copper)      .10
16-35      Flange Gasket                 .10
16-48      Insert Gasket                 .10
21-519     Throttle Stop Damper Control
             and Shaft Assembly
22-1       Heater Jacket Plug            .20
23-8       Air Screw Shell               .50
24-6       Choker Spring                 .15
24-116     Air Valve Spring              .30
24-28      Flusher Spring                .15
24-50      Metering Pin Spring           .15
24-51      Ratchet Spring                .15
25-524     Choker Shaft and Spring
             Assembly                    .75
27-10      Choker Fly                    .25
30-504     Float and Lever Assembly      .75
33-501     Float Shaft Assembly          .20
35-501     Float Valve Assembly          .45
36-4       Strainer Connection to Bowl   .40
38-501     Insert Connection Screw       .50
43-508     Gasoline  Adjusting Needle
            Assembly                     .50
44-1       Gasoline Adjusting Needle
            Packing                      .10
45-1       Gasoline Adjusting Needle
            Packing Nut                  .15
49-56      High Speed Jet                .30
56-508     Bowl Cover Assembly           .75
58-501     Flusher Assembly              .15
64-1       Bowl Support                  .10
65-1       Brass Bowl                   2.50
65-502     Brass Bowl Assembly          6.00
66-3       Metering Pin Lock Wire        .05
67-1       Strainer Body                 .30
67-502     Strainer Assembly            1.00
78-1       Throttle Shaft Washer         .05
78-5       3/16 Lock Washer              .05
79-8       Metering Pin Housing Space    .20
80-3       Metering Pin Plug             .15
81-16      Strainer Nut                  .15
82-1       Cotter Pin                    .05
83-2       Manifold Stud                 .05
84-3       Metering Pin Jet              .35
95-1       Strainer Gauze                .20
119-504    Dash Pot Plunger, Plunger
          Rod and Washer Assem.          .80
125-2      Metering Pin Spring Seat      .05
158-2      Metering Pin Housing          .15
167-502    Metering Pin Stem and
             Wire Assembly               .10
173-529    Metering Pin and Lock Wire
             Assembly                    .45


REPLACEMENT FOR PREVIOUS MODEL NASH SIXES

The Model "S" Marvel Carbureter is interchangeable with the Model "K"
Marvel Carbureter, which was standard equipment on the 1922 and 1923
Nash Sixes of the early 691 series.

The previous series 681 Nash Sixes of 1921, 1920, and 1919, which were
equipped with the Model "E" Marvel Carbureter as standard equipment, can
be very greatly improved by the installation of the Model "S"
carbureter, exhaust damper body assembly necessary for same, and the hot
air stove assembly that goes with this installation.

Following is the complete Parts Price List of the Model "S" carbureter,
damper body assembly and stove parts for same. Notice is called to the
fact again that the damper body and stove parts are not needed on the
early 691 series of 1922 and 1923.


REPLACEMENT PARTS PRICE LIST For 1919-1922 Series 681 Nash Sixes

10-579    Carbureter and Heat Equipment
            Complete                       $30.00

Consisting of the Following Parts:

Part No.      Name                          Price

10-580   Carbureter Assembly          1     22.00
128-506  Damper Body and Stove
           Assembly                          8.00
15-16    10×24×3/8   F.H. Machine
           Screw                      1   $   .05
15-43    1/4×20×1/2 Std. Square
           Head Set Screw             2       .05
15-53    5/16×18×2-1/2 Cap Screw      1       .05
15-54    3/8×16×1 Standard Square
           Head Set Screw             2       .05
17-14    Exhaust Shut-off Valve
           Connecting Rod             1       .10
17-15    Damper Connecting Rod
           (Main Damper)              1       .20
19-2     Exhaust Manifold Damper
           Fly                               1.00
19-9     Warm Air Stove Damper
           Fly                        1
20-31    Stove Damper Fly Shaft       1       .10
24-31    Damper Fly Shaft Spring      1       .10
24-43    Stove Damper Fly Spring      1       .15
28-4     Connecting Rod Swivel        1       .25
62-5     Escutcheon Pin               1       .05
74-3     Exhaust Shut-off Valve       1       .15
78-4     5/16 Plain Washer            1       .05
81-26    3/8×16 Check Nut             2       .05
82-1     1/16×1/2 Cotter Pin          2       .05
82-3     1/8×3/4 Cotter Pin           3       .05
100-16   Warm Air Stove               1
100-17   Warm Air Stove               1
100-520  Warm Air Stove Assembly      1      1.50
122-503  Damper Lever and Shaft
           Assembly                   1      1.00
122-504  Exhaust Shut-off Lever
           and Shaft Assembly         1       .40
123-1    Heat Tube Support Ring       1       .10
123-3    Damper Body Packing
           Stop Ring                  1       .10
123-4    Exhaust Damper Body
           Packing Ring               1       .10
124-1    Heat Tube Collar             4       .20
125-1    Damper Shaft Spring
           Seat                       2       .10
126-2   Heat Tube Outlet              1       .50
126-12  Heat Tube Inlet               1       .50
127-1   Heat Tube Packing             4       .10
127-2   Exhaust Damper Body
          Packing, per foot           1       .10
128-3   Exhaust Damper Body           1      3.00
128-506 Exhaust Manifold Damper
           Body and Stove Assembly    1      8.00
163-1   Choker Rod Extension                  .10


MARVEL CARBURETER DISTRIBUTORS

Distributors who carry a complete stock of Carbureters and Parts and who
are prepared to overhaul and rebuild Carbureters:

Marvel Carbureter Sales Co.,
335 Newbury Street, Boston, Mass.

Marvel Carbureter Sales Co.,
242 West 69th Street, New York, N.Y.

Marvel Carbureter Sales Co.,
2120 Fourteenth Street, N.W., Washington, D.C.

Marvel Carbureter Sales Co.,
6520 Carnegie Avenue, Cleveland, Ohio.

Marvel Carbureter Sales Co.,
1406 McGee Street, Kansas City, Mo.

Marvel Carbureter Sales Co.,
2119 S. Michigan Avenue, Chicago, Ill.

Marvel Carbureter Sales Co.,
926-928 E. Washington Street, Indianapolis, Ind.

Marvel Carbureter Sales Co.,
1138 Broadway, Denver, Colo.

Marvel Carbureter Sales Co.,
1837 South Flower Street, Los Angeles, Calif.

Edwards Warden Motor Parts Co.,
309-315 E. Broadway, Salt Lake City, Utah.

Fauver-Cavanagh Co., Inc.,
46-52 Canfield Avenue E., Detroit, Michigan.

McAlpin & Schreiner Co.,
1520 Tenth Avenue, Seattle, Washington.

Moloney Battery & Ignition Co.,
108-110 Wyoming Street, El Paso, Texas.

W.S. Nott Company,
Second Ave. N. & 3rd Street, Minneapolis, Minn.

Distributors who carry a complete stock of Carbureters and Parts:

Auto Supply Co., Inc.,
1107-1111 Broadway, Nashville, Tenn.

Herrick Hardware Co.,
Waco, Texas.

Joseph Schwartz Company,
729-735 St. Charles Street, New Orleans, La.

Shelton Motor Company,
Abeline, Texas.

Wholesale Auto Supply House,
309-311 Washington Street, Tampa, Florida.

Westbrook Motor Co.,
San Antonio, Texas.


EXPORT BUSINESS

All export business and shipments handled by Overseas Motor Service
Corporation, 1760 Broadway, New York, N.Y.

[Illustration: THE FLINT PRINTING CO.]





End of Project Gutenberg's Marvel Carbureter and Heat Control, by Anonymous