MARVELCARBURETERANDHEAT CONTROL AS USED ONSERIES 691 NASH SIXES BOOKLETS MARVEL CARBURETER CO. FLINT, MICHIGANU. S. A. MODEL "S" CARBURETER Used on Series 691 Nash Sixes The carbureter measures the fuel charges for the engine andautomatically mixes them with the proper amount of air to form a highlycombustible gas. The Marvel Model "S" Carbureter is of the automatic airvalve, 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 completevaporization 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 aconventional float chamber bowl with fuel strainer attached at point ofentrance of fuel to bowl. Within the mixing chamber are two nozzleswhich proportion the amount of gasoline used in the mixture. One ofthese nozzles, called the "low speed, " is regulated by the gasolineadjustment screw at bottom of carbureter and the other, called the "highspeed, " is controlled by the automatic air valve. An air screw isprovided which regulates the pressure of the air valve spring enclosedtherein. Within this screw is also enclosed a plunger connected by alink to the air valve. The function of this plunger is to provide aresistance in addition to that of the air valve spring to assist inacceleration. This arrangement of plunger and air valve screw is termedthe dash pot. A further control of the high speed jet is provided by the fuel meteringvalve operated by the carbureter throttle. This valve provides themaximum fuel feed to the "high speed" nozzle when the throttle is fullyopened for high speeds and for quick "pick up. " During the ordinarydriving ranges this valve controls the amount of fuel being used, thusproviding all the economy possible. This valve is entirely automatic andrequires no adjustment. The passage-way from the mixing chamber to the intake manifold iscontrolled by a butterfly valve which is called the throttle-valve andis connected to the throttle-lever on the steering wheel as well as tothe foot accelerator, its position determining the amount of gas and airor mixture being fed the engine. STARTING A choke button is provided on the instrument board to assist instarting. Pulling out this button closes a butterfly choker valve (seecut) in the air intake passage of carbureter which restricts the airopening of the carbureter, and consequently produces a richer mixture. To start engine, pull out choke button all the way. Advance spark leverabout half way and throttle lever about one-quarter way and depressstarter pedal. As soon as motor fires when starting, this control should be releasedpart way, otherwise too much fuel will be drawn from carbureter, causingflooding of the motor and failure of the latter to continue to promptlyfire. After starting, motor should be allowed to run "part choke" asstated for a few minutes while warming up, then the choker controlshould be fully released, or pushed in completely on the instrumentboard, and engine allowed to run normally for sometime until water incylinder jackets is thoroughly warmed up before starting to make finalcarbureter adjustments. HEAT CONTROL--STOVE In the colder seasons warm air is fed to air intake of carbureterthrough the warm air elbow "F" (see cut). This elbow connects thecarbureter with the warm air stove, which is a casting surrounding thetwo exhaust heat tubes which supply exhaust heat to the carbureterjackets as described below. The amount of heat required for proper carburation depends on thetemperature of the outside air. The first means of control is in thewarm air stove just described, which should be connected to thecarbureter furnishing warm air to carbureter air intake in all seasonsof the year when the outside air temperature is below 50° F. , wheneverthe outside air temperature runs above this point cold air should befurnished to carbureter air intake. This can be done by loosening thewing nut holding the warm air elbow "F" on the stove and also looseningthe set screw holding this elbow in the air intake of carbureter, afterwhich slide elbow out of air intake and revolve it--180 degrees about anhorizontal axis and re-insert in carbureter air intake and lock in placewith set screw. The opening in the elbow now is turned down away fromthe stove and draws in only cold air. The above procedure, it must be understood, will vary somewhat due todifferences in locality, altitude and fuels used, but it should be bornein mind that the best economy can be had with cold air passing to thecarbureter, and the stove should not be connected until the accelerationand performance of the job requires the use of warm air for the bestresults. The adjustment of the carbureter should be made per the abovedescription of the stove, as the latter is used for meeting weatherconditions and should be set as described. HEAT CONTROL--CARBURETER JACKETS The carbureter and manifolds have been designed to utilize the exhaustgases of the engine to insure complete vaporization and a consequentminimum consumption of fuel. This is accomplished by surrounding theupper portion of the mixing chamber with a large heat jacket providedwith an inlet and an outlet opening and connected by means of tubes toan exhaust manifold valve body in the exhaust pipe of the engine; thisvalve body, housing a large valve called the main-exhaust-heat-valve("C" in cut) within the body itself, the return or outlet tube from thecarbureter heat jacket entering the valve-body in the lower portionbelow the main-exhaust-heat-valve. The main-exhaust-heat-valve "C" is connected by means of a lever andlong connecting rod to the throttle lever of the carbureter so that whenthe throttle valve is operated the main-exhaust-valve is operatedsimultaneously with it. The purpose of the carbureter heat jacket and valve in exhaust line withconnections described, is to provide means for utilizing the heat of theexhaust gases of the motor for vaporization of the fuel supplied theengine by the carbureter and to do so automatically. The automaticfeature of same is accomplished by setting the Main-Exhaust-Heat-Valve"C" by means of the long connecting rod, in closed position with theclosed or idling position of the throttle valve, thus providing for andcausing all of the exhaust gases of the engine to pass through the heatjacket of the carbureter when engine is idling and to regulate thevolume of this heat as throttle is opened by automatically opening theMain-Exhaust-Heat-Valve, thus allowing the increasing volume of theexhaust gases to pass on out through the main exhaust pipe without beingdeflected and by-passed to the carbureter heat-jacket as the motor speedincreases. [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 closedwith the closed or idling position of the throttle valve. Thisadjustment is accomplished by having long connecting rod "R" from valve"C" Lever set in "Hole No. 1, " in Throttle Lever "L, " being sure thatwhen throttle valve is standing in fully closed or idling position thatvalve "C" is also in closed position, proving out the latter feature byloosening connection of valve "C" lever holding long connecting rod;holding Throttle Lever "L" in closed or idling position and bringing upvalve "C" lever on connecting rod "R" as far as it will go to the righttoward the carbureter and tightening its connection on the connectingrod in that position. After having made the adjustment as justdescribed, it is assured that "Heat Setting No. 1" has been properlymade and that all of the heat possible from the exhaust has beensecured. This "Heat Setting No. 1, " provides as stated, for the most exhaust heatobtainable and should be used during the entire year, except inextremely hot seasons or hot climates or when high-test gasoline isbeing used in engine and even then unless engine is losing power due toexcessive heat. If loss of power or mileage due to too much heat is experienced, firstbe 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 tocut (See Page 7) describing "Heat Setting No. 2. " It will be noted thatconnecting rod "R" from valve "C" is removed from "Hole No. 1, " inThrottle Lever "L" and placed in "Hole No. 2, " in Throttle Lever. Thischange is all that is necessary in order to reduce the amount of heatapplied to carbureter. In "Heat Setting No. 2, " when the throttle is inclosed or idling position, valve "C" is quite aways off its seat. Thisadjustment provides for a great deal less heat than is provided by "HeatSetting No. 1" and is all that is required in the reduction of thevolume of heat together with driving on "Cold" air for themain-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 "HeatSetting No. 1" do not again readjust valve "C" on connecting rod butwhen changing from "Heat Setting No. 1" to "Heat Setting No. 2, " merelychange 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 aninspection has been made to determine if the trouble is in some otherunit. It should be noted that the gasoline lines are clear, that thereis gasoline in the vacuum tank, that there are no leaks at connectionsbetween carbureter and engine, that the ignition system is in propercondition, and that there is even compression in all cylinders. If it is necessary to test adjustment or to make a readjustment proceedas follows: Set air screw so that the end is flush with the end of ratchet setspring. Loosen packing nut on needle adjustment. Turn gasolineadjustment to the right very carefully so as not to injure the needlepoint, until the valve is closed gently against its seat. Then turn toleft approximately one complete turn which will bring notch in the dischandle directly below the guide post above it. Tighten packing nut tohold needle firmly as set. The notch in disc handle of needle is put in handle after the needle hasbeen carefully calibrated by a flow-meter at the factory, therefore thenotch in handle should register with guide post above it. This settingof needle valve is absolutely essential to get the best results. Theobject in directing that needle be first turned to the right untilclosed is to insure against two or more turns open, as from closedposition to notch (usually about one turn) is the normal setting. Thisbeing true it is not necessary to turn needle in to the right firmly butmerely far enough to be sure that when turning back to the left, to thenotch registering with guide post, that the needle is not more than oncearound or one turn from its seat. Set stove heat and damper heat as previously instructed above. Pull outchoker to closed position and start engine in usual manner. As soon asengine has fired release choker three-fourths of way in. Run untilengine has warmed up then push choker all the way in, remembering tonever use choker longer than necessary, as when not needed it has atendency to foul up engine and ruin the lubricating oil in the crankcase. Next, set air screw for good idle by either turning to the right alittle 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. Withthe needle so set and the engine warmed up, the adjustment of the airscrew 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 airscrew is not tight enough, the motor will hesitate and perhaps stopentirely. To make a nice clean adjustment for idle, first having setneedle as described, turn air screw in quarter of a turn at a time untilengine, does roll; then turn back to the left until engine hesitates, indicating that mixture has too much air and is too lean; next turn airscrew in to the right three or four notches at a time until engine runssmoothly. This accomplished (and it is very easy to do by proceeding asdirected above) the proper adjustment for the entire range of the enginewill 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 beadjusted by means of the throttle lever adjusting screw. RICH MIXTURE An over-rich mixture will cause the engine speed to fluctuate throughmore or less regular periods from high to low speeds; the engine willseem to be mis-firing and there will be noticeable a strong odor, aswell as, usually, a heavy black smoke from the exhaust. LEAN MIXTURE The best adjustment is obtained with the fuel and air valves set asdescribed. It must be remembered that too lean a mixture as well as anover rich mixture causes over-heating and loss of power and is not aseconomical as an adjustment which provides just the proper proportion ofgasoline and air. CAUTION It must be remembered that the low speed needle has been carefullycalibrated to notch in disc handle and guide post above it, at thefactory and that in making an adjustment that the needle must be so setand the rest of the adjusting done with the air screw as described, never varying from described needle setting unless in extreme coldweather, when a little more gas may be carried, or turning off a littlewhen 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. 0010-580 Carbureter Assembly 22. 0011-537 Insert Assembly 7. 0012-77 Accelerator Lever . 4012-78 Throttle Lever . 4014-2 Throttle Fly . 2515-5 10×24×1/2 Insert Lock Screw . 0515-6 Bowl Support Screw . 0515-14 Ratchet Spring Screw . 0515-15 Bowl Cover Screw . 0515-23 Throttle and Choker Fly Screws . 0515-28 Throttle Stop Adjusting Screw . 0515-29 6-32×1/4" French Head Screw . 0515-32 Pilot Set Screw . 0515-43 Square Head Set Screw . 0516-5 Bowl Cover Gasket . 0516-14 Strainer Gasket (fibre) . 0516-16 Strainer Gasket (Copper) . 1016-35 Flange Gasket . 1016-48 Insert Gasket . 1021-519 Throttle Stop Damper Control and Shaft Assembly22-1 Heater Jacket Plug . 2023-8 Air Screw Shell . 5024-6 Choker Spring . 1524-116 Air Valve Spring . 3024-28 Flusher Spring . 1524-50 Metering Pin Spring . 1524-51 Ratchet Spring . 1525-524 Choker Shaft and Spring Assembly . 7527-10 Choker Fly . 2530-504 Float and Lever Assembly . 7533-501 Float Shaft Assembly . 2035-501 Float Valve Assembly . 4536-4 Strainer Connection to Bowl . 4038-501 Insert Connection Screw . 5043-508 Gasoline Adjusting Needle Assembly . 5044-1 Gasoline Adjusting Needle Packing . 1045-1 Gasoline Adjusting Needle Packing Nut . 1549-56 High Speed Jet . 3056-508 Bowl Cover Assembly . 7558-501 Flusher Assembly . 1564-1 Bowl Support . 1065-1 Brass Bowl 2. 5065-502 Brass Bowl Assembly 6. 0066-3 Metering Pin Lock Wire . 0567-1 Strainer Body . 3067-502 Strainer Assembly 1. 0078-1 Throttle Shaft Washer . 0578-5 3/16 Lock Washer . 0579-8 Metering Pin Housing Space . 2080-3 Metering Pin Plug . 1581-16 Strainer Nut . 1582-1 Cotter Pin . 0583-2 Manifold Stud . 0584-3 Metering Pin Jet . 3595-1 Strainer Gauze . 20119-504 Dash Pot Plunger, Plunger Rod and Washer Assem. . 80125-2 Metering Pin Spring Seat . 05158-2 Metering Pin Housing . 15167-502 Metering Pin Stem and Wire Assembly . 10173-529 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 1923Nash Sixes of the early 691 series. The previous series 681 Nash Sixes of 1921, 1920, and 1919, which wereequipped with the Model "E" Marvel Carbureter as standard equipment, canbe very greatly improved by the installation of the Model "S"carbureter, exhaust damper body assembly necessary for same, and the hotair 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 thefact again that the damper body and stove parts are not needed on theearly 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. 00128-506 Damper Body and Stove Assembly 8. 0015-16 10×24×3/8 F. H. Machine Screw 1 $ . 0515-43 1/4×20×1/2 Std. Square Head Set Screw 2 . 0515-53 5/16×18×2-1/2 Cap Screw 1 . 0515-54 3/8×16×1 Standard Square Head Set Screw 2 . 0517-14 Exhaust Shut-off Valve Connecting Rod 1 . 1017-15 Damper Connecting Rod (Main Damper) 1 . 2019-2 Exhaust Manifold Damper Fly 1. 0019-9 Warm Air Stove Damper Fly 120-31 Stove Damper Fly Shaft 1 . 1024-31 Damper Fly Shaft Spring 1 . 1024-43 Stove Damper Fly Spring 1 . 1528-4 Connecting Rod Swivel 1 . 2562-5 Escutcheon Pin 1 . 0574-3 Exhaust Shut-off Valve 1 . 1578-4 5/16 Plain Washer 1 . 0581-26 3/8×16 Check Nut 2 . 0582-1 1/16×1/2 Cotter Pin 2 . 0582-3 1/8×3/4 Cotter Pin 3 . 05100-16 Warm Air Stove 1100-17 Warm Air Stove 1100-520 Warm Air Stove Assembly 1 1. 50122-503 Damper Lever and Shaft Assembly 1 1. 00122-504 Exhaust Shut-off Lever and Shaft Assembly 1 . 40123-1 Heat Tube Support Ring 1 . 10123-3 Damper Body Packing Stop Ring 1 . 10123-4 Exhaust Damper Body Packing Ring 1 . 10124-1 Heat Tube Collar 4 . 20125-1 Damper Shaft Spring Seat 2 . 10126-2 Heat Tube Outlet 1 . 50126-12 Heat Tube Inlet 1 . 50127-1 Heat Tube Packing 4 . 10127-2 Exhaust Damper Body Packing, per foot 1 . 10128-3 Exhaust Damper Body 1 3. 00128-506 Exhaust Manifold Damper Body and Stove Assembly 1 8. 00163-1 Choker Rod Extension . 10 MARVEL CARBURETER DISTRIBUTORS Distributors who carry a complete stock of Carbureters and Parts and whoare 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 ServiceCorporation, 1760 Broadway, New York, N. Y. [Illustration: THE FLINT PRINTING CO. ]