US3342465A

US3342465A - Carburetor

Info

Publication number: US3342465A
Application number: US558516A
Authority: US
Inventors: Jesse L Szwargulski; Raymond G Hennemann
Original assignee: ACF Industries Inc
Current assignee: ACF Industries Inc
Priority date: 1966-06-17
Filing date: 1966-06-17
Publication date: 1967-09-19
Anticipated expiration: 1984-09-19

Description

SePt' 19, 1967 1.1., szwARGuLsK| ETAL 3342465 CARBURETOR original Filed Deo. 31, 1964 3 Sheets-Sheet 1 INVENTORS JESSE L. SZWARGULSKI BYF'AYMOND G. HENNEMANN AGENT SeP- 19, 1967 J. L. szwARGULsKl ETAL. 3342465 CARBURETOR Original Filed Dec. 31, 1964 3 Sheets-Sheet 5 INVENToRs JESSE L. SZWARGULSKI BY RAYMOND G. HENNEMANN AGENT United States Patent O 6 Claims. (Cl. 261-52) This application is a continuation of our presently abandoned application, Serial No. 426,466, filed December 31, 1964 and Serial No. 426,466 is a continuation of abandoned application Serial No. 101,706, filed April 10, 1961.

This invention is di'rected to a carbu'retor for an internal combustion engine.

Carburetors for small internal cornbustion engines adapted for utility power pl'ants used with lawnmo'wers, outboard marine engines and the like are normally ope'rated by a single control which is adapted to position the choke and throttle valves for various desired speeds and condition of operation. It is desirab'le that the fabrication of such carburetors be simple and that costs be minimized. It is also an advantage in the fabrication and also in the operation of such carburetors that the controls `be mounted 'on the carburetor independently of other assembled parts. This feature simplifies assembly p'rocedures.

It is therefore an object of this invention to provide a novel carburetor for an internal combustion engine which has simplified controls.

It is another object of the invention to provide a novel carburetor for 'an internal combustion engine in which the control mechanis-m has a minimum number of parts.

It is a further object of the invention to provide a novel carburetor for an internal combustion engine in which the control mechanism is fabricated of simple elements and of minimum cost.

rllhe invention as hereinafter described is one in which the controls for a carburetor have been readily incorporated and designed of simple structural elements. The carburetor comprises a tubular member defining a mixtu-re conduit and a metal cup for a fuel bowl. The fuel bowl and mixture conduit are fixed together by a common bolt assembly, which is also utilized -as the main fuel nozzle of the ca'rburetor, as well as providing a restricted area in the mixture conduit fo'r a pressure reducin'g venturi effect. The control mechanism comprises a single lever mounted to one end of the |bolt assembly and adapted for manual -movement, which movement positions the throttle and choke valves as required for varied Operating conditions.

FIG. 1 is a view in elevation of a carburetor, having mounted thereon the control assembly in accordance with the invention.

FIG. 2 is 'a plan view of the carburetor and control assembly of FIG. 1.

FIG. 3 is a partial, longitudinal sectional view of the carburetor an'd control assembly of PIG. 2 as viewed along section 'lines 3-3.

FIG. 4 is a transverse sectional view of the carbu'retor and control assembly of FIG. 2 along section lines 4-4.

FIGS. 5, 6 and 7 are pa'rtial plan views of the carburetor of FIGS. 1 and 2 with the control plate removed to show the control assembly in diiferent operative positions.

The carburetor consists of a tubular mixture conduit structure 10, defined by a sheet metal tube of uni'form cross sectional area, having a straight portion 12 at one end and a curved portion 14 at the other end. A fiange r'ce 16 is fixed to the curved end 14 of the mixture conduit and provides means for attaching the carburetor to the manifold M of an engine. Attachment may be in an appropriate manner as by threaded bolts 18, or similar fastening devices extending through fiange 16 and threaded into mating openings in the manifold M.

The other end of mixture conduit 10 engages an air filter housing 20, which consists of a rectangular metal boX structure 23 formed of sheet metal in which one side 22 comprises a detachable metal plate and a cover for the air filter. The air filter structure 23 defines a central portion terminating in a cylindrical collar 24` which en- `gages the tubular end of the conduit portion 12, as shown in FIGS. 1 and 6. Cover plate 22 of air filter housing 20 is formed with a pair of longitudinal flange members 26 which fit over the side walls of the box structure 20, and which include small indentations 28 for fitting into apertures 30 through the side walls of the box structure 20. The in'dentations 28 and apertures 30 form a means for detac'halbly fastening the cover plate 22 to the air filter housing structure.

Cover plate 22 includes a plura'lity of longitudinal louvers 32 which are bent inwardly and provide inlet openings through the cover for air entering the mixture conduit 10. Also, the ends of the air filter housing 23 are open for the adrnission of air into the housing. The 'housing itself is provided with an air filte-ring material, such as spun glass or a Sponge plastic material, through which :air may pass and the -dirt particles therein filtered out. The air filter material 34 is formed in the shape of a rectangular block which fits snugly into the box structure 23 of the air filter.

Depending from the straight tubular portion 12 -of mixture conduit 10, is a lfuel bowl 36 which is cut-shaped and cy'lindrical in form. The open end of the fuel bowl 36 is closed by a fuel bowl cover 38, which is formed to fit the circular top edge 'of the bowl 36. Fitted between the fuel bowl 36 and the cover 38 is a fuel resistant gasket 40 for preventing fuel leak'age between the bowl and its cover 38.

A single bolt assembly 42 is used for holding and fixing mixture conduit 10 rigidly to the fuel bowl 36 'and the 'fuel 'bowl cover 38. The ybolt 42 includes an elongated shank portion extending through the bottom of fuel bowl 36, alon'g the central -axis thereof, through an appropriate aperture 37 in the fuel bowl cover. Said shank at the upper end traverses the center of the conduit portion 12 substantia-lly normal to the aXis of the conduit 10. The lower portion of bolt assembly 42 within the fuel 'bowl 36 is of slightly greater diameter than the upper portion 44 of the bolt assembly passing through the conduit 10. Between these two bolt 'assembly portions of different diameters there is thus formed a shoulder 46. Aperture 37 in fuel bowl cover 38 approximates the diameter of the lbolt portion 44 so that shoulder 46 rests against the under side of the fuel bowl cover for tightly holding the latter to the conduit structure 10. The upper portion of bolt assembly 42 engages a nut 48.

Referring to FIG. 3 in assembling the carburetor, bolt assembly 42 is passed through the several carburetor parts and positioned with the shoulder 46 of the bolt assembly against the underside of the fuel bowl cover 38. Tightening down of nut 48 against the upper surface of the conduit structure 12 tightens the fuel bowl cover 38 against gasket 49 positioned between the fuel bowl cover and conduit 10.

The lower end of bolt assembly 42 has an enlarged threaded bore 50, which at the outer end thereof, which receives a bolt 52 having a head 54. Fuel bowl 36 is attached to the bolt assembly 42 by headed bolt 52 which firmly presses the fuel bowl from its lower side to force the upper lip of bowl 36 against the flanged rim of the bowl cover 38 with the fuel resistive gasket 40 in between.

Bolt assembly 42 is formed with an elongated passage 56 extending at least partially therethrough along its aXis from the boring 50 upwardly into the upper bolt section 44. Ports 58 in the lower end of bolt assembly 42 define passageways communicating fuel bowl 36 with enlarged bore 50. Ports '58 communicate the fuel bowl to the axial passage 56 for passing fuel to the latter.

At the upper end of passage 56 other ports 60 are formed, communicating passage 56 to the central region of conduit 10. Ports l60 rnay be four in number, as shown in PIG. 6 leading outwardly at 90 degrees from each other from passage 56. Ports 60 are positioned preferably, substantially on a common plane through the axis of the conduit portion 12, and normal to the axis of bolt assembly 42. Within the upper portion of passage 56 and below ports 60 there is positioned a metering restriction element 62 into which an adjusting needle 64 partially extends. Needle 64 has a portion 66 threaded into the upper end of bolt 42 to provide axial movement of the needle 64 in restriction 62. Adjustrnent of the needle 64 is made by use of a screw driver slot 68 at the other end of needle 64.

A choke valve 70 is mounted on a choke valve shaft 72 journaled through apertures in the conduit walls at `portion 12 between the air filter 20 and the upper end 44 of bolt 42. A choke Operating lever 74 is attached to one end of the choke shaft 72 protruding from the conduit. Choke valve 70 itself is an elliptical metallic member having a transverse axis slightly greater than the diameter of the conduit portion 12, and a conjugate axis substantially equal to the diameter of conduit portion 12. Functionally the choke valve 70, upon being turned from its opened position, shown in FIG. 6, to a closed position, will abut the inner wall of tubular conduit portion 12, which provides a stop means for the choke valve.

A throttle valve 76 is mounted for rotational movement within conduit portion 12 on a throttle shaft 78, which is likewise journaled to conduit walls at one end in a recess '80. The latter is formed in the wall of conduit portion 12 and at the opposed end in an aperture 82 through the wall of the conduit. Throttle Operating lever 84 is fixed to one extended end of the throttle shaft 78 extending from conduit 12, substantially parallel to the end of choke shaft 72. Throttle valve 76 is formed in a manner similar to choke valve 70 with an elliptical configuration so that the Wall of conduit portion 12 provides a stop means for the throttle plate, when the latter rotated to its closed position, as shown in PIG. 3.

Refern'ng to FIG. 2, fuel is delivered to fuel bowl 36 from a remote tank T by any -appropriate means, grav- -ity feed for example. A needle valve 90 is slidably mounted within an enlarged passage 89 of fitting 88 and includes a sharp conical point 91 at one end to cooperate with a valve seat structure 92 of fitting 88.

Valve 90 is operatively controlled by a float mechanism which consists of a fioat structure 94, attached to a float lever 96. One end of lever 96 is hinged about a pin -100 supported by an arm structure 102 from the inlet fitting 88. The other end of fioat lever 96 forms a valve Operating arm 104, which abuts the adjacent end of the needle valve 90. In the usual manner, the level of the fuel within bowl 36 determines whether fuel will flow past valve 90. When the fuel level in bowl 36 reaches a predetermined point, the float arm 104, acted upon by float 94, forces the needle valve 90 against its seat 92 to close the flow of fuel in the fuel bowl through inlet fitting 88.

In operation, air sucked into manifold M is drawn through the air filter thence through mixture conduit 10. During normal operation of the engine, choke valve 70 is in a wide open position, as indicated in FIG. 3. Also, the throttle 76 is disposed between a partially open to wide open position. Thus, air can flow through the carburetor, and conduit 10, into manifold M.

Air fiowing through the conduit portion 12 is forced into the restricted regions between the upper bolt portion 44 and the inner wall surface of conduit portion 12. These restricted regions provide a venturi effect, in which the high Velocity flow of air around the surface of bolt portion 44 establishes a sub-atmospheric pressure in these regions. This subatmospheric pressure condition aspirates fuel under atmospheric pressure from the bowl 36 through ports 58 into the passage 56 and upwardly through the metering restriction 6.2. From restriction 62, fuel fiows from ports 60. The ports 60, directed in an upstrearn direction of the air flow, permits some air to flow into the upper end of passage 56 to mix the fuel and pass out of the downstream passages 60 as a mixture of fuel and air. Needle 64 is adjusted to provide the desired amount of fuel for part throttle and wide open throttle conditions of operation.

The carburetor includes an idling system for low speed or idling operation, and consists of a tube 106 extending into the fuel bowl at one end and having its other end press-fitted into the fuel bowl cover 38 and supported thereby. The fuel bowl cover is contoured to form projecting Shoulders 107 and a semicylindrical supporting surface 108 which provides a cradle into which the mixture conduit portion 12 fits and is held in a fixed position. A recess 110 (FIGS. 3 and 4) is formed in the cylindrical surface 108 and extends beneath and around the throttle shaft journaling recess 80.

The upper end of idle tube 106 extends through fuel bowl cover 38 into recess 110. Gasket 49 seals the recess 110 from fuel fiow between the cover 38 and conduit 10. An idle port 112 is formed in the wall of conduit 10 and an aperture 113 is formed through gasket 49 to provide passage of idle fuel from recess 110 into the mixture conduit 10. An idle adjustment screw 114 is threaded vertically through the upper wall of conduit 10, as shown in FIG. 3. Screw 114 has a pointed needle end 116 extending into idle port 112 to provide a manual control for idle mixture flow through port 112.

During operation of the idle system, throttle 76 is normally closed or nearly closed. The high vacuum provided on the downstream side of throttle 76 is sufiicient to draw fuel from bowl 36 through idle tube 106 into recess 110 and out of the idle port 112. The fitting of the carburetor parts is such, however, that with throttle 76 fully closed, additional air will flow around the throttle and mix with the idle fuel from port 112 to provide a mixture of fuel and air suflicient for engine idling purposes.

Mounted on the bolt assembly 42 is a control plate 118. Plate 118 is fixed to the top of the fuel adjusting needle 64, which is threaded at 117 to receive a nut 120. In assembling the control plate 118 to the carburetor structure, an ear or L-shaped tab 124 at the end of plate 118 is positioned within a slot 126 in the upper side wall of the air filter housing 23. Plate 118 is then brought down onto the sleeve 122. Portion 66 of needle 64 is thereafter inserted through aperture 119 in plate 118 and threaded into the upper portion of bolt -assembly 42. Nut is threaded onto needle portion 117 and is tightened to force plate 118 against the end of sleeve 122, which in turn rests against the top of nut 48.

In accordance with the invention, a control lever structure 128 is indepndently journaled on the sleeve 122. A spring washer 130 fixed between sleeve 122 and nut 48 has portions spring-biasing the control lever 128 upwardly against the control plate 118. A dimple 132 (FIGS. 4 and 5) is struck upwardly out of the surface of control lever 128 to cooperate with

apertures

133 and 135 formed in the control plate 118. Under action of the spring washer 130, 'dimple 132 will ride into

apertures

133 and 135 as the control lever 118 is rotated from one position to another. Control lever 128 has a plurality of Operating arms or extensions for controlling operation of the carburetor.

One arm 134 (PIG. 4) extends downwardly from an upper surface of lever 128. A coil spring 136 has one end attacheid to lever arm 134 and the other end attached to the throttle control lever 84. A second arm 138 of control lever 128 forms a handle for operating the control lever 128, and also has an aperture 140 to which may be attached a Bowden cable 142 for Operating control lever 128 from a distance.

A coil spring 143 (FIGS. 1, 3, and 7) is mounted on bushing 122 and is arranged with one end 144 rigidly held by the central portion of control lever 128. The other end of spring 143 consists of a straight section 146 extending from the bushing 122 into an aperture formed in an arm 148 of the choke control lever 74. Throttle valve 76 of the carburetor is also Controlled by a governor device, such as an air fan and movable diaphragm, attached to a Wire 150 connected to the throttle lever 84.

In the operation of the engine and motor, starting of the motor is initiated by closing choke valve 70. This is done by moving the control lever 128 to its farthest position to the right, as viewed in FIGS. 1, 2, and 5, for example. Such movement is accomplished by means of the manual lever 138 or the Bowden cable 142. Control lever 128 in the position shown in FIG. 5, biases arm 134 of the lever against the straight portion 146 of spring 143, which rotates the choke lever 74 counterclockwise to a substantially closed position. The closed position of the choke valve provides sufficient air flow through conduit 10 for starting the engine. It also insures an enriched mixture for starting. Control lever 128, in the choking position, further holds the throttle valve in a Wide open position by its connection to the throttle lever 84 through arm 134 and spring 136. The throttle is thus held opened against any spring bias tending to close the throttle, which may be exerted by the governor control or other means.

As the engine starts, the control lever is moved clock- Wise, as viewed in FIGS. 2 and 6, into the first intermediate position, shown in FIG. 6, in which dimple 132 rides into aperture 133. In this first intermediate position, the throttle valve 76 is still held in an open position. High speed operation of the engine will cause the engine governor through Wire 150 and throttle lever 84 to move throttle 76 to a more closed position against the bias of spring 136, depending upon the desired speed. The movement of the control lever 128 from its choke or start position to the first intermediate position, as described above, allows arm 134 of control lever 128 to release the end 146 of spring 143, so that under the action of spring 143, the choke lever 74 is rotated clockwise, as viewed in FIG. 6, to a full open position at which it is retained during the other control positions of lever 128. A second arm 156 on the choke valve lever 74 abuts a portion of the air cleaner 20 to provide a stop means for positioning the choke valve 70 in the wide open position and as seen in FIG. 7.

Movement of the control lever 128 to the second intermediate position, in which the dimple 132 rides into the aperture 135, closes throttle 76 (FIGURE 7). This results, since spring 136 becomes a rigid connector between the control lever arm 134 and the throttle lever 84. This is the idle position of the engine. With the throttle closed, insufi'icient air passes through conduit 10 to operate the high speed or main fuel system, so that no fuel flows through the outlet ports 60. The idle operation of the carburetor is as described above, in which the fuel is drawn through only the idle port 112.

Movement of the control lever 128 to the farthest left position as shown in FIGS. 2 and 7, holds the throttle 76 in its closed position and in some modifications, one of the arms of control lever 128 may be positioned to contact an electrically live terminal of the engine ignition system to ground the ignition system and stop the engine. Operating arm 138 of control lever 128, as shown in FIGS. 2 and 4,

6 for example, extends through an opening 151 in the control plate structure 118.

Edges

152 and 154 of this aperture 151 provide a stop structure for the Operating arm 138, when in its extreme positions.

The carburetor structure described above is one which is made virtually entirely of sheet metal fabricated parts. The conduit 10 is preferably sheet metal tubing, While the fioat fuel bowl 36 comprises a simple s'heet metal, drawn cup. Float bowl cover 38 is also formed of sheet metal 'drawn into the shape as described, consisting of the projecting Shoulders 107 and the semi-cylindrical supporting surface 108 with the idle passage 110. The air cleaner box structure 20 is also formed entirely of sheet metal. The L- shaped tab 124 of the control plate 118 serves to lock the air cleaner 20 to the mixture conduit 10 and to prevent its rotation or removal.

The single bolt assembly 42, thus, supports and locks all the carburetor parts together by tightly holding the fuel bowl cover 38 to the fuel conduit mixture conduit 10 and the fuel bowl to this assembly through bolt 54. Upper threaded end 117, of the adjusting needle 64 provides effectively an extension of the bolt 42, and mounts the control plate 118 and control lever 128 to the rest of the assembly. Also, in accordance with the in'vention, the control assembly consisting of lever 128, springs 143 and 136, is mounted on the carburetor independently of the assembly of the carbure-tor parts.

The carburetor can be operated by alternate arrangements than that presently'described. However, the design of the present control assembly permits the latter to be assembled on the carburetor as a separate subassembly Without changing the design or arrangeme'nt of the carburetor parts. Furthermore, the control assembly comprises 'essentially one lever and two springs, which in themselves are of simplfied inexpensive design, yet permit operation of both the choke and throttle valves by a single control.

As will be readily seen, lthe configuration disclosed in the foregoing is not the only way of employing the novel features peculiar to this invention.

What we claim is:

1. A carburetor for an internal combustion engine including:

(A) a fuel bowl,

(B) a Wall defining a tubular mixture conduit,

(C) a throttle valve, mounted in said mixture conduit and including:

(l) a throttle shaft having one end thereof extending through said wall of said mixture conduit.

(D) a choke valve mounted in said mixture conduit and including:

(l) a choke valve shaft having one end thereof extending through said mixture conduit wall,

(E) a bolt assembly including:

(1) a shank disposed transversely through said mxture conduit and said fuel bowl respectively, and a bolt carried on the shank urging said conduit and fuel bowl into engagement one to the other,

(2) said shank having an elongated passage eX- tending at least partially therethrough and having an outlet port communicating With said m'ixture conduit, whereby fuel may be directed from said fuel bowl to said mixture conduit,

(F) said shank having a head portion extending from said wall of said miXture conduit,

(G) a Valve shaft actuating means rotatably carried on said shank head portion, and

(H) connecting means operably engaging said valve shaft actuating means with said throttleI shaft and said choke shaft, respectively, whereby said shaft actuating means may be adjusted to simultaneously actuate said throttle and said choke Valves for regulating the mixture flow passing through said mixture conduit.

2. In a carburetor as defined in claim 1 including: (A) a choke operating lever carried on said choke shaft end extending from said mixture conduit, (B) spring means carried on said shank head portion and engaging said choke Operating lever for biasing the latter in response to rotated movement of said valve shaft actuating means.

3. In a carburetor as defined in claim 2 wherein said spring means includes:

(A) a spring having an elongated arm protruding therefrom,

(B) said elongated arm being in engagement with choke Operating lever to bias the latter for actuating said choke valve in response to rotated movement of the valve shaft actuating means.

4. A carburetor including:

(A) a fuel bowl,

(B) a mixture conduit having an upper Wall, and being positioned downwardly adjacent said fuel bowl,

(C) a throttle valve plate jonrnaled in said mixture conduit and including:

(1) a throttle valve shaft supporting said throttle valve plate and having an end thereof protrudi'ng through said mixture conduit upper wall,

(D) a ehoke valve plate journaled in said mixture conduit and including:

(1) a choke valve shaft supporting said choke valve plate and having an end thereof protruding through said mixture conduit upper Wall,

(E) a bolt assembly disposed in said bowl and mixture conduit and including,

(1) an upright shanlc connected to said bowl and said conduit, engaging said respective members for positioning the same with respect to each other,

(a) means in said upright shank orming a passage communicating said mixture conduit with the lower portion of said bowl for directing fuel to the latter,

(b) an end portion of said shank protruding beyond said conduit upper wall in a direction substantially parallel to said respective throttle and choke shaft,

(F) a valve shaft actuating member rotatably carried on said shank end portion adapted to be connected to external control means for rotating said actuating member about said shank end,

(G) a first spring connected to said throttle valve shaft and to said valve shaft actuating member,

(H) a second spring carried on said shank upper end and having an arm depending therefrorn in engagement with said choke valve shaft,

(I) Whereby rotation of said shaft actuating member will bias said respective valve shaft ends for regulating the settings of said throttle and choke valve.

5. In a carburetor as defined in claim 4 wherein:

(A) said choke valve shaft is being journalled in said mixture conduit for rotational movement between a first position to open said mixture conduit to airfiow therethrough, and a second portion to close said mixture conduit to air flow therethrough,

(B) Said second spring includes another arm extending therefrom and engaging said actuating member, said second spring being movable in response to movement of said actuator for biasing said choke valve shaft between said open and closed positions.

6. In a carburetor as defined in claim 4 including:

(A) a lever carried at the extending end of said respeetive choke and said valve shaft,

(B) said first spring being connected to said actuating member and 'said lever being carried on said throttle shaft, said second spring being connected to said actuator and said lever being carried on said choke shaft.

References Cited UNITED STATES PATENTS 1,018,164 2/1912 Chapin et al 261-52 2,799,486 7/ 1957 Teschendorf et al. 3,089,685 5/1963 Hennernann et al 261-64 3,093,699 6/1963 Dernitz 261-65 HARRY B. THORNT ON, Primary Examiner.

FRANK W. LUTTER, Examner.

R. R. WEAVER, Assistant Examiner.

Claims

1. A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE INCLUDING: (A) A FUEL BOWL, (B) A WALL DEFINING A TUBULAR MIXTURE CONDUIT, (C) A THROTTLE VALVE, MOUNTED IN SAID MIXTURE CONAND INCLUDING: (1) A THROTTLE SHAFT HAVING ONE END THEREOF EXTENDING THROUGH SAID WALL OF SAID MIXTURE CONDUIT. (D) A CHOKE VALVE MOUNTED IN SAID MIXTURE CONDUIT AND INCLUDING: (1) A CHOKE VALVE SHAFT HAVING ONE END THEREOF EXTENDING THROUGH SAID MIXTURE CONDUIT WALL, (E) A BOLT ASSEMBLY INCLUDING: (1) A SHANK DISPOSED TRANSVERSELY THROUGH SAID MIXTURE CONDUIT AND SAID FUEL BOWL RESPECTIVELY, AND A BOLT CARRIED ON THE SHANK URGING SAID CONDUIT AND FUEL BOWL INTO ENGAGEMENT ONE TO THE OTHER, (2) SAID SHANK HAVING AN ELONGATED PASSAGE EXTENDING AT LEAST PARTIALLY THERETHROUGH AND HAVING AN OUTLET PORT COMMUNICATING WITH SAID MIXTURE CONDUIT, WHEREBY FUEL MAY BE DIRECTED FROM SAID FUEL BOWL TO SAID MIXTURE CONDUIT, (F) SAID SHANK HAVING A HEAD PORTION EXTENDING FROM SAID WALL OF SAID MIXTURE CONDUIT, (G) A VALVE SHAFT ACTUATING MEANS ROTATABLY CARRIED ON SAID SHANK HEAD PORTION, AND (H) CONNECTING MEANS OPERABLY ENGAGING SAID VALVE SHAFT ACTUATING MEANS WITH SAID THROTTLE SHAFT AND SAID CHOKE SHAFT, RESPECTIVELY, WHEREBY SAID SHAFT ACTUATING MEANS MAY BY ADJUSTED TO SIMULTANEOUSLY ACTUATE SAID THROTTLE AND SAID CHOKE VALVES FOR REGULATING THE MIXTURE FLOW PASSING THROUGH SAID MIXTURE CONDUIT.