Rollover shutoff valve assembly for carburetor

A rollover shutoff valve assembly used with a carburetor inhibits leaking of fuel from the carburetor in circumstances where the vehicle has rolled over so that the carburetor is inverted from the normal operating position. The rollover shutoff valve assembly includes a fluid passage, a race and a plug received in the race. The plug is movable in the race to inhibit liquid flow through the passage when the shutoff valve assembly rotates from an upright position to an inverted position. The races are closed except at the passage.

FIELD

The present disclosure relates generally to a valve assembly for inhibiting fuel leakage from a carburetor in the event of a vehicle rollover.

BACKGROUND

Carburetors are used to deliver a fuel-air mixture to an engine for combustion. Carburetors typically include a main body through which a stream of air from the air intake passes to the manifold, and in which gasoline is fed into the air stream. A fuel bowl holding a reservoir of gasoline is mounted on the main body by a meter block through which a measured flow of gasoline is aspirated from the fuel bowl to the air stream in the main body. One face of the meter block forms a wall of the fuel bowl which is usually about halfway immersed in the gasoline in the fuel bowl. The opposite face of the meter block engages the main body at an interface. A typical meter block includes a plurality of passages that extend from the fuel bowl face through the main body face to fluidly connect the interior of the fuel bowl to the interior of the main body. These passages can include fuel delivery passages, venting passages, air bleed passages and the like. The fuel bowl and the passages through the meter block are arranged so that liquid fuel cannot escape the carburetor when it is in an upright orientation. But when a vehicle is involved in a rollover collision that inverts the carburetor, fuel from the fuel bowl can flow through the passages in the meter block, into the carburetor main body and outside of the carburetor, where it can create a serious combustion hazard.

DETAILED DESCRIPTION

Referring now to the drawings and in particular toFIG. 1, a carburetor is illustrated schematically and is generally indicated at1. The illustrated carburetor is a four barrel carburetor of the type used on a vehicle, but can be any type of carburetor used for any type of gasoline engine. The carburetor includes a main body2and first and second fuel bowls3from which fuel is drawn to mix with air for feeding into an engine (not shown). Each of the fuel bowls3is mounted on the main body2of the carburetor1by a respective meter block6. Each meter block6includes a fuel bowl face6A that forms a wall of the fuel bowl and an opposite main body face6B that engages a respective side wall portion12of the main body2at a sealed interface. InFIG. 1, the carburetor is shown in an upright orientation. Throughout this disclosure, terminology describing the vertical orientation or positioning of the features of the carburetor1will be understood to refer to the carburetor or components of the carburetor in the upright position as shown inFIG. 1. Thus, the upright orientation shown inFIG. 1provides the frame of reference for terms such as “top,” “bottom,” “upper,” “lower,” “upward,” and “downward” throughout this disclosure. In the upright orientation, a float assembly (not shown) maintains the level of fuel in the respective fuel bowl3at an upright fuel level UFL. At the upright fuel level UFL, the fuel bowl face6A of each meter block is only partially immersed in fuel.

As is known in the art, various passages (not shown) extend through each meter block6to fluidly connect the interior of each fuel bowl3to atmosphere and the main body of the carburetor. For example, in certain conventional meter blocks, one or more fuel discharge passages, one or more air bleed passages, and/or one or more fuel bowl vent passages may extend through the meter block to fluidly communicate between the interior of the fuel bowl and atmosphere and/or the interior of the main body2of the carburetor (e.g., a barrel of the carburetor). Some of these passages typically extend from an opening formed in the fuel bowl face6A of the meter block6to an opening formed in the main body face6B of the meter block. The openings formed in the fuel bowl face6A may be located above or below the upright fuel level UFL, depending on the purpose of the passage. The carburetor1must have fluid communication paths to atmosphere to draw in air to mix with the liquid fuel. Moreover the fuel bowls require communication with atmosphere to prevent a vacuum effect. The required paths allow fuel to escape the carburetor in rollover situations (which is understood to mean rotation of the carburetor about a horizontal axis from the upright orientation of at least about 90°). As explained below, the present disclosure relates to a rollover shutoff valve assembly that may be installed in the carburetor1to prevent fuel from entering the main body of the carburetor and subsequently escaping the carburetor in the event of a rollover accident.

Referring toFIG. 2, in one conventional carburetor, openings formed in the main body surface6B of each meter block6are arranged in register with ports that are formed in a respective side wall portion12of the main body2. In the illustrated embodiment, each side wall portion12of the main body2includes left and right idle air bleed ports14L,14R, left and right main fuel supply ports15L,15R, left and right main air bleed ports16L,16R, and a bowl vent port17that are substantially aligned along a horizontal line located above the upright fuel level UFL. As is understood in the art, these ports are aligned with respective passages extending through the meter block6, and the meter block passages (not shown) can provide pathways for fuel to leak from the fuel bowl3into the main body2and out of the carburetor1when the carburetor is turned from an upright position, such as in rollover situations. In addition to the aligned ports located above the upright fuel level UFL, the side wall portion12of the main body2also defines a discharge nozzle port18, left and right curb-idle discharge ports19L,19R, and left and right idle-transfer slot ports20L,20R. As is understood in the art, when the carburetor1becomes inverted, these ports align with passages extending through the meter block6that would not typically be expected to allow liquid fuel to flow into the main body2. In addition to the ports described above, the side wall portion12of the main body2defines a manifold vacuum chamber21for operatively receiving a portion of a power valve (not shown) of the carburetor1therein as is known in the art. In addition to the ports, the side wall portion12of the main body2defines a plurality of threaded holes22for threadably receiving screws (not shown) for mounting the respective fuel bowl3and meter block6on the main body2.

Referring toFIG. 3, a rollover shutoff valve assembly, generally indicated at101, may be installed in the carburetor1at each interface between the meter block6and the side wall portion12of the main body2, to inhibit fuel spillage in a rollover event. It is understood that the shutoff valve assemblies101may be installed as a retrofit installation in an existing carburetor or be installed by a carburetor manufacturer as an original component in a carburetor assembly. Other configurations are envisioned. For example, the shutoff valve assembly may be part of the meter block or the main body of the carburetor. As shown inFIGS. 4-7, each shutoff valve assembly101includes a valve body103that defines four mounting holes104that are shaped and arranged for being positioned in register with the threaded holes22of the side wall portion12of the main body2. Thus, each valve assembly101may be mounted on the main body2along with the meter block6using screws (not shown) that extend through the mounting holes104and are threadably received in the threaded holes22. To permit a retrofit of the shutoff valve assembly101in an existing carburetor, longer screws (not shown) may be provided in a kit with the shutoff valve assembly101.

Referring toFIGS. 4-10, each shutoff valve assembly101includes a valve body103that has a top end portion and a bottom end portion spaced apart along a height BH of the body extending along a vertical center axis VCA (FIG. 4). The valve body103further includes a meter block face103A (FIGS. 4 and 6) and a main body face103B (FIGS. 5 and 7) that are spaced apart along a thickness BT of the body (FIG. 8). The valve body103also has a right side portion and a left side portion disposed on opposite sides of the vertical center axis VCA and spaced apart along a width BW of the body (FIG. 4). In the illustrated embodiment, various features of the shutoff valve assembly101are mirrored on each side of the vertical center axis VCA. Mirrored features of the shutoff valve assembly101shown on the right side of the vertical center axis VCA as shown inFIG. 4are indicated with a reference number ending in the letter R; mirrored features shown on the left side of the vertical center axis as shown inFIG. 4are indicated with a reference number ending in the letter L. It is understood that the terms left and right are used in this disclosure in reference to the appearance of the shutoff valve assembly101as shown inFIG. 4, and the orientation of the shutoff valve assembly, and thus the features thereof, will vary in use.

The valve body103defines a plurality of passages extending through the thickness BT of the body that are shaped and arranged to communicate between the ports14L,14R,15L,15R,16L,16R,17in the side wall12of the main body2and the corresponding openings (not shown) in the main body face6B of the meter block6. In the illustrated embodiment, the valve body103defines left and right idle air bleed passages114L,114R, left and right main fuel supply passages115L,115R, left and right main air bleed passages116L,116R, and a bowl vent passage117. When the shutoff valve assembly101is mounted in the carburetor, the passages114L,114R,115L,115R,116L,116R,117are substantially aligned along a horizontal line located above the upright fuel level UFL in registration with the respective ports14L,14R,15L,15R,16L,16R,17to convey air between the meter block6and the main body2of the carburetor1. The shutoff valve assembly101is configured to automatically close the passages114L,114R,115L,115R,116L,116R,117when the carburetor becomes inverted as in a rollover situation. As explained in further detail below, the valve body103defines races that are aligned along the width BW of the shutoff valve body with the passages114L,114R,115L,115R,116L,116R,117and that are each configured to guide movement of a respective plug129to a position in which the plug blocks the respective passage when the carburetor1becomes inverted (FIGS. 6 and 7).

In addition to the passages114L,114R,115L,115R,116L,116R,117, the shutoff valve assembly also defines a discharge nozzle passage118, left and right curb-idle discharge passages119L,119R, and left and right idle-transfer slot passages120L,120R that are respectively shaped and arranged to provide fluid communication across the thickness BT of the shutoff valve assembly body103between the main body ports18,19L,19R,20L,20R and the respective openings (not shown) in the main body face6B of the meter block6. It will be understood that a valve body may define other arrangements of passages that are shaped and positioned to operatively communicate between the ports in a carburetor main body and the corresponding openings in a meter block. The shutoff valve assembly body103also defines a power valve hole121that allows the body of a power valve (not shown) to pass through the shutoff valve assembly101and be operatively received in the manifold vacuum chamber21of the main body12.

As shown inFIG. 8, the valve body103comprises first and second housing members141,143that are secured together to form the shutoff valve body. In one or more embodiments, the first and second housing members141,143are formed from a metal such as aluminum, but other materials may also be used without departing from the scope of the invention. The first housing member141includes the meter block face103A of the valve body103, and the second housing member143includes the main body face103B of the shutoff valve body. Each of the housing members141,143has about the same height and width such that when the housing members are secured together, the valve body103has a substantially smooth and continuous perimeter edge margin. As shown inFIG. 11, the first housing member141defines a first pair mounting holes145and a first group of four mounting holes146. As shown inFIG. 13the second housing member143defines a second pair of mounting holes147that are shaped and arranged to align with the first pair of mounting holes145of the first housing member141, and further defines a second group of four mounting holes148shaped and arranged to align with the first group of four mounting holes146of the first housing member. The groups of four mounting holes146,148in the first and second housing members141,143are arranged around the power valve hole121. In the illustrated embodiment, the mounting holes145,146,147,148are threaded, and the mounting holes145,146formed in the first housing member141are countersunk. Screws149thread through the aligned first and second pairs of mounting holes145,146. Screws150thread through the aligned first and second groups of mounting holes147,148. The first pair of mounting holes145and first group of mounting holes146are countersunk on the exterior face of the first housing member141. Because the mounting holes145,146are countersunk, the heads of the screws149,150are recessed below the meter block surface103A of the valve body103so as not to interfere with the meter block6when the shutoff valve assembly101is installed in the carburetor101. Referring toFIGS. 4 and 5, dowel holes151are formed in the first and second housing members141to receive alignment dowels (not shown) of the meter block6when the shutoff valve assembly101is installed in the carburetor.

Referring toFIGS. 4 and 6, the first housing member141has an outer surface that forms the meter block face103A of the valve body103, an inner surface for opposingly engaging second housing member143, and a thickness TH1extending from the outer surface to the inner surface. It is understood that in other embodiments the first housing member could form the main body face of the body instead of the meter block face. As shown inFIGS. 11-13, the first housing member141defines a plurality of holes extending through the thickness TH1that are shaped and arranged to form portions of the shutoff valve passages114L,114R,115L,115R,116L,116R,117,118,119L,119R,120L,120R,121. Specifically, the first housing member141defines left and right idle air bleed holes214L,214R, left and right main fuel supply holes215L,215R, left and right main air bleed holes216L,216R, a bowl vent hole217, a discharge nozzle hole218, left and right curb-idle discharge holes219L,219R, left and right idle-transfer slot holes220L,220R, and a power valve hole221that form portions of the respective passages114L,114R,115L,115R,116L,116R,117,118,119L,119R,120L,120R,121. In the illustrated embodiment, each of the holes has a circular shape, but other embodiments can include holes having other shapes without departing from the scope of the invention.

Referring toFIGS. 11 and 12, the first housing member141defines a plurality of elongate primary grooves254L,254R,255L,255R,256L,256R,257that are spaced apart along the width BW of the valve body103in substantial alignment with the holes214L,214R,215L,215R,216L,216R,217. Specifically, the illustrated housing member141defines left and right idle air bleed primary grooves254L,254R that are aligned with the left and right idle air bleed holes214L,214R, left and right main fuel supply primary grooves255L,255R that are aligned with the left and right main fuel supply holes215L,215R, left and right main air bleed primary grooves256L,256R that are aligned with the left and right main air bleed holes216L,216R, and a bowl vent primary groove257that is aligned with the bowl vent hole217. As explained in further detail below, each of the primary grooves254L,254R,255L,255R,256L,256R,257forms a portion of a respective race that guides movement of the respective plug129to close one of the passages114L,114R,115L,115R,116L,116R,117when the shutoff valve assembly101becomes inverted.

Each primary groove254L,254R,255L,255R,256L,256R,257is formed in the inner surface of the first housing member141. Each primary groove254L,254R,255L,255R,256L,256R,257has a groove depth extending along the thickness TH1of the first housing member141from the inner surface of the first housing member. In one or more embodiments, the groove depth is greater than about one-half of the thickness TH1of the first housing member141but less than the entire thickness of the first housing member. In the illustrated embodiment, the groove depth is substantially constant along the respective race. But in other embodiments the depth of the primary groove may vary without departing from the scope of the invention. As will be explained in further detail below, in the illustrated embodiment each primary groove254L,254R,255L,255R,256L,256R,257defines the entire depth of the respective race. Thus, the primary groove depth is equal to the race depth in the illustrated embodiment.

Each primary groove254L,254R,255L,255R,256L,256R,257extends from a bottom end portion to a top end portion along a height that defines the height RH1, RH2, RH3of the respective one of the races. Each hole214L,214R,215L,215R,216L,216R,217is located along the height RH1, RH2, RH3of the respective race adjacent the top end portion of the respective primary groove254L,254R,255L,255R,256L,256R,257. In the illustrated embodiment, the main fuel supply races formed by primary grooves255L,255R have the first race height RH1, the air bleed races formed by primary grooves254L,256L,254R,256R have the second race height RH2, and the bowl vent race formed by primary groove257has the third race height RH3. The first race height RH1is taller than the second race height RH2, and the second race height is taller than the third race height RH3. The short third race height RH3prevents the bowl vent primary groove257from intersecting the discharge nozzle hole218, which is located directly below the bowl vent hole217along the vertical center axis VCA. As explained in further detail below, the difference between the first race height RH1of main fuel supply races and the shorter second height RH2of the air bleed races accounts for the differences in pressures at the main fuel supply passages115L,115R and the air bleed passages114L,114R,116L,116R during use of the carburetor1.

The primary grooves254L,254R,255L,255R,256L,256R,257each have a groove width extending between the left side portion and the right side portion of the primary groove. As explained below, the width of each primary groove defines the width of the respective race; thus the primary groove width is equal the race width in the illustrated embodiment. In the illustrated embodiment, the width of each primary groove254L,254R,255L,255R,256L,256R,257varies along the height RH1, RH2, RH3of each race. More specifically, the width of each primary groove254L,254R,255L,255R,256L,256R,257is widest at the top end portion of the primary groove and tapers inward as it extends downward such that the primary groove is narrowest at the bottom end portion of the primary groove. For example, in the illustrated embodiment, each of the left and rights side portions of each primary groove254L,254R,255L,255R,256L,256R,257is slightly skewed with respect to the vertical center axis VCA. The left and right side portions extend inward toward one another as they extend from the top end portion to the bottom end portion of the primary groove254L,254R,255L,255R,256L,256R,257. As explained in further detail below, the slightly sloped sides of the primary grooves254L,254R,255L,255R,256L,256R,257ensure that the shutoff valve assembly101functions to close the passages114L,114R,115L,115R,116L,116R,117, even when the carburetor1is only rotated by about 90° about a horizontal axis from the upright orientation (e.g., in a collision that causes a vehicle to roll over onto its side).

As shown inFIGS. 9 and 11, a secondary groove264L,264R,265L,265R,266L,266R,267(broadly, a “recess”) extends from the bottom of the respective primary groove254L,254R,255L,255R,256L,256R,257, further into, but not through the first housing member141along a portion of the height RH1, RH2of the races. Each secondary groove264L,264R,265L,265R,266L,266R,267has a length that extends from a bottom end that is spaced apart above the bottom end of the respective primary groove254L,254R,255L,255R,256L,256R,257to a top end that spaced apart below the top end of the respective primary groove and from the bottom end of the respective hole214L,214R,215L,215R,216L,216R,217. In the case of secondary groove267, its shape is circular in the illustrated embodiment. Each secondary groove264L,264R,265L,265R,266L,266R,267has a width that is slightly narrower than the width the respective primary groove254L,254R,255L,255R,256L,256R,257. Likewise, the diameter of each of the holes214L,214R,215L,215R,216L,216R,217is narrower than the width of the respective primary groove254L,254R,255L,255R,256L,256R,257. As explained in further detail below, the secondary grooves264L,264R,265L,265R,266L,266R,267remove material from the bottom of each primary groove254L,254R,255L,255R,256L,256R,257to reduce contact area between the plug129and valve body and therefore reduce frictional resistance to closing the shutoff valve assembly101. Similar secondary grooves (not shown) could be provided in the interior face of the second housing member143to further reduce frictional resistance to movement of the plug129with respect to the valve body103.

A perimeter channel270is formed in the interior face of the first housing member141. The perimeter channel270(FIG. 11) can receive a portion of a gasket272(FIG. 17) that extends continuously around the perimeter of the first housing member141. When assembled with the second housing member143, the gasket is compressed between the first and second housing members141,143to seal the interior of the shutoff valve assembly101. Similarly, a channel274(FIG. 11) is formed in the interior face of the first housing member141around the power valve hole221. The channel274may receive an O-ring276(FIG. 17) that is compressed between the first and second housing members141,143when assembled. The O-ring276seals, in essence, an inner periphery of the shutoff valve assembly. Thus, any migration of fuel between the various holes and races in the shutoff valve assembly is completely contained within the shutoff valve assembly between the O-rings272and276. In addition, channels280(FIG. 11) formed around two of the mounting holes104on the interior face of the first housing member receive O-rings282(FIG. 17). In normal operation, these two O-rings282are around only the mounting holes104that are the bottom of the shutoff valve assembly101. In that position fuel flows more readily through the shutoff valve assembly and these O-rings282inhibit leakage. However, it will be understood that O-rings (not shown) could be added around all of the mounting holes104within the scope of the present invention. Channels284(FIG. 11) around left and right curb-idle discharge holes219L,219R, on the interior face of the first housing member141receive O-rings286(FIG. 17). Similarly, channels288(FIG. 11) around left and right idle-transfer slot holes220L,220R have O-rings290(FIG. 17). The curb-idle discharge ports19L,19R and idle-transfer slot ports20L,20R (formed in part by the holes219L,219R,220L,220R) also normally are on a lower part of the shutoff valve assembly101and the O-rings286,290inhibit leakage of fuel from the shutoff valve assembly.

Referring toFIGS. 13 and 14, the second housing member143has an outer surface that forms the main body face1036of the shutoff valve body103, an inner surface configured to opposingly engage the inner surface of the first housing member141, and a thickness TH2extending from the outer surface to the inner surface. The second housing member143defines a plurality of holes extending through the thickness TH2that are shaped and arranged to form portions of the shutoff valve passages114L,114R,115L,115R,116L,116R,117,118,119L,119R,120L,120R,121. Specifically, the second housing member143defines left and right idle air bleed holes314L,314R, left and right main fuel supply holes315L,315R, left and right main air bleed holes316L,316R, a bowl vent hole317, a discharge nozzle hole318, left and right curb-idle discharge holes319L,319R, left and right idle-transfer slot holes320L,320R, and a power valve hole321that form portions of the respective passages114L,114R,115L,115R,116L,116R,117,118,119L,119R,120L,120R,121. In the illustrated embodiment, each of the holes has a circular shape, but other embodiments can include holes having other shapes without departing from the scope of the invention. The second housing member143is constructed to close off the primary grooves254L,255L,256L,254R,255R,256R,257to form the races.

Referring toFIGS. 10, 11 and 15-17, the shutoff valve assembly101includes a plurality of plugs129that are sized and arranged for being movably received in the races. In one or more embodiments, the plugs129are formed from a metal such as brass, but other materials may also be used without departing from the scope of the invention. In the illustrated embodiment, each plug129has a short, cylindrical shape and comprises a first end and a second end spaced apart from one another along a thickness PT (FIG. 16) of the plug. Suitably, the thickness PT of each plug129is slightly smaller than the depth GD of the respective primary groove254L,254R,255L,255R,256L,256R,257(and thus the depth of the respective race). In the illustrated embodiment, each primary groove254L,254R,255L,255R,256L,256R,257has the same depth GD, so each plug129has the same thickness PT. But in other embodiments, the races may have different depths and consequently the plugs may have different thicknesses. Each plug129has a circular cross-sectional shape having a plug diameter PD. Suitably, the diameter PD of each plug129is slightly smaller than the width of the respective primary groove254L,254R,255L,255R,256L,256R,257at the top end portion thereof and larger than the diameters of the passages114L,114R,115L,115R,116L,116R,117. In other words, each plug129is sized and shaped to be movably received in the respective race and to substantially block the respective passage114L,114R,115L,115R,116L,116R,117. Since the widths of the top end portions of the primary grooves254L,254R,255L,255R,256L,256R,257are about the same, the diameters of all of the plugs129are likewise about the same. But it will be understood that in other embodiments the diameters of the plugs may vary to correspond with primary grooves having varying widths.

In the shutoff valve assembly101, one plug129is movably received in each race formed by the primary grooves254L,255L,256L,254R,255R,256R,257in the first housing member141and the opposing interior face of the second housing member143. The first end of each plug129slidably engages the interior wall of the first housing member141, and the second end of each plug slidably engages the interior wall of the second housing member143. Thus, the plugs129are slidably captured in the races between the first and second housing members141,143to substantially inhibit movement of the plugs in the direction of the thickness BT of the valve body103. The elongate secondary grooves264L,264R,265L,265R,266L,266R,267in the first housing member141reduce the size of the contact area between the first and second ends of the plugs129and the housing member141. Similar secondary grooves (not shown) could be formed in the second housing member143. The reduced contact area reduces the frictional engagement between the plugs129and the valve body103and thus enhances sliding of the plugs along the heights RH1, RH2, RH3of the races.

The circular perimeter surface of each plug129is received between the left and right side portions of the respective primary groove254L,254R,255L,255R,256L,256R,257for rolling and/or sliding along the side portions of the primary groove, along the height RH1, RH2, RH3of the respective race. Since the thickness PT and the diameter PD of each plugs129are smaller than the thickness and width of the primary grooves254L,254R,255L,255R,256L,256R,257, the plugs are permitted to slide or roll along the heights RH1, RH2, RH3of the races as the orientation of the shutoff valve assembly changes in use. For example, when the orientation of the shutoff valve assembly101changes from upright to inverted, the plugs129roll from respective upright positions (FIG. 17) adjacent the first end portions of the races, to respective inverted positions (FIG. 18) at the second end portions of the races. Because the side portions of the primary grooves254L,255L,256L,254R,255R,256R,257are sloped with respect to the vertical center axis VCA of the shutoff valve body, the round plugs129will tend to roll along the side portions of the primary groove walls, even when the shutoff valve body is only inverted about 90° from the horizontal orientation

In the inverted position (FIG. 18), the plugs129are sized and arranged to block the passages114L,114R,115L,115R,116L,116R,117. When the plugs are positioned in the second end portions of the races124L,124R,125L,125R,126L,126R,127as shown inFIGS. 6, 7, and 18, they inhibit liquid flow through the shutoff valve passages114L,114R,115L,115R,116L,116R,117. Thus, when the carburetor1becomes inverted and the plugs129slide from the first end portions of the primary grooves254L,254R,255L,255R,256L,256R,257to the second end portions, the plugs subsequently inhibit fuel from leaking out of the fuel bowls3through the shutoff valve passages114L,114R,115L,115R,116L,116R,117.

Thus, it can be seen that in use the shutoff valve assemblies101provide protection against fuel leaks that might be caused by inversion of the carburetor1. With the shutoff valve assemblies101installed between the meter blocks6and the main body2, the carburetor1can operate normally in the upright orientation to deliver a fuel-air mixture to a vehicle engine. When the carburetor1is in use, the plugs129remain seated in their upright positions shown inFIGS. 4, 5, and 17. The main fuel supply passages115L,115R are pressurized by the flow of fuel from the fuel bowls3into the main body2of the carburetor. But because the main fuel supply races have relatively tall heights RH1, the respective plugs129are seated at a position that is spaced apart from the pressurized main fuel supply passages115L,115R by a substantial distance. As a result, the pressure in the fuel supply passages115L,115R is attenuated at the bottom end portions of the races125L,125R and does not cause the plugs129to move upward along the heights RH1of the races125L,125R in use.

When a rollover accident occurs that causes the carburetor1to rotate about a horizontal axis from the upright position by at least about 90°, each of the plugs129moves along the height RH1, RH2, RH3of the respective race from the upright position to the inverted position, where it blocks fluid flow through a respective passage114L,114R,115L,115R,116L,116R,117. More specifically, the round plugs129roll or slide along the side portions of the primary grooves254L,254R,255L,255R,256L,256R,257of the first housing member141and the outer wall of the second housing member143to the inverted position (FIG. 18). In the inverted position, the plugs129are positioned to partially or completely block fluid flow through the passages114L,114R,115L,115R,116L,116R,117and thus limit the amount of fuel that leaks from the fuel bowls3out of the carburetor1.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.