Abstract: To allow an intake negative pressure to directly act on a fuel outlet formed on a nozzle tube, and to guide a fuel discharged from the fuel outlet in the nozzle tube to the fuel-air mixture passage. A rotary carburetor (200) has a guide plate member (42) downstream of a fuel outlet (30) located in a through-hole (14). The guide plate member (42) has both side edges (42b) away from an inner wall surface (14a) of the through-hole (14). The through-hole (14) is divided by the guide plate member (42) into a first passage portion (44) and a second passage portion (46). The first passage portion (44) communicates through a piston groove with a scavenging passage of a cylinder. The fuel discharged from the fuel outlet (30) is guided by the guide plate member (42) to the second passage portion (46) and is supplied through the second passage portion (46) to a fuel-air mixture passage (24) of an engine intake system.

Abstract: In a carburetor, three downstream body passages in the body communicate with three valve passages in the valve element, and the valve element rotates between a closed position and an opened position. The carburetor is a one-bore type carburetor in which the body passages and the valve passages are respectively partitioned with the body partitions and the valve partitions. When rotating the valve element from the closed position to the opened position, the second body passage and the second valve passage for mixture start to communicate in advance than the first and third body passages and the first and third valve passages for air.

Abstract: A plunger valve. The plunger valve includes a body, where the length of the body is between 13 millimeters and 20 millimeters. The plunger valve also includes a set of flutes on the body. The set of flutes includes at least four flutes. The set of flutes are each symmetrically spaced about the axis of the needle-shaped plunger. The plunger valve further includes a conical tip.

Abstract: A carburetor including a columnar throttle valve, a fuel nozzle, a metering needle inserted into the fuel nozzle and a cam mechanism caused to rotate in accordance with the throttle operation, whereby the throttle valve is moved by the cam mechanism in the direction of the valve stem while rotating to adjust the air flow rate and the fuel flow rate. The cam mechanism has a cam groove provided with a cam surface so as to gradually deepen in the direction of rotation in a designated range on the external peripheral side of the bottom surface of the throttle valve, and a support pin for supporting the throttle valve from the bottom surface, wherein the support pin being disposed between the cam surface and the bottom surface of the columnar throttle valve chamber rotatably provided with the throttle valve.

Abstract: A dust seal structure for a valve stem in a rotary throttle valve The dust seal structure has a cylindrical throttle valve with a metering needle and a throttle through-hole, and a fuel nozzle disposed on the central axis of the throttle valve that is openable into the throttle through-hole with the metering needle inserted therein. The valve stem of the throttle valve, which protrudes at one end from the shaft hole formed in the cover body of a valve hole in the carburetor body, is caused to rotate in accordance with the operation of the accelerator pedal, whereby the throttle valve moves in the direction of a central axis thereof while rotating as a whole, and controls airflow and fuel-flow rate. A dust-proof member composed of a sealing ring is fitted between the valve stem and the shaft hole formed in the cover body.

Abstract: A carburetor has a carburetor housing in which an air passage and a mixture passage are disposed. A barrel valve controls the air passage and the mixture passage. The barrel valve has a mixture passage section and an air passage section formed therein. The air passage in at least one position of the barrel valve is closed off at least partially by the barrel valve. The air passage in the at least one position of the barrel valve in which the air passage is at least partially closed off by the barrel valve is connected by a connection within the barrel valve with the mixture passage. An internal combustion engine equipped with such a carburetor exhibits excellent running behavior.

Abstract: A rotary carburetor in which a cam mechanism for causing the throttle valve to move in the direction of the valve stem can be accommodated without the accompanying enlargement of the main section of the carburetor.

Abstract: The invention is a rotary throttle valve carburetor that minimizes frictional drag on the airflow through the air intake passage. This is accomplished by providing bearing shafts at both ends of the rotary throttle valve body upon which are mounted ball bearings such that upon assembly of the rotary throttle valve body to the carburetor body housing, friction free rotation is established as the rotary throttle valve body is rotated by an accelerator cable from idle to full throttle position. The rotary valve carburetor also features a rotary throttle valve body assembly which by the use of end caps mounted to the rotary throttle valve body provides the ability to vary the venturi effect within the air intake passage by exchanging the rotary throttle valve body assembly and associated end caps with a different face angle so as to create a different venturi effect by the air passing through the air intake passage of the carburetor body housing.

Abstract: A carburetor of a remote control model has a main body axially bored with an axial hole that is installed with a throttle and a second needle in its one side and provided with a female-threaded section formed at a certain portion of its other side for engaging with a male-threaded section of an adjustment valve. The adjustment valve possesses a fuel entering passage formed axially with a dead end, and an injection nozzle formed at the end corresponding to and for a needle valve of the second needle to move to and fro therein. And, the adjustment valve is directly installed in the axial hole without being accompanied with other components, effective to lower progressive tolerance between the injection nozzle and the needle valve to provide uniform fuel injection.

Abstract: A valve is used with a carburetor, and the carburetor therefor. The valve has a throttle valve and an air valve. The air valve defines an air bore and has a baffle disposed within the air bore. The baffle separates one section of the air bore from another section, and impedes airflow through the air bore during at least some positions of the air valve.

Abstract: The present invention provides an internal shape of a rotor for a two-bore rotary carburetor used in a stratified scavenging engine whereby an engine for a power saw, lawn mower, or the like can be stabilized in the course of a complete change in orientation during idling. A groove pocket (10) in communication with a fuel supply-side bore (8) is formed at the aperture edge of each of the upstream end and the downstream end of a carburetor rotor valve (6) toward an accelerated rotation direction in the fuel supply-side bore (8) of the rotor valve (6). The groove pocket (10) is shaped so as to gradually rise and decrease in cross-sectional surface area toward the accelerated rotation direction along a peripheral surface of the rotor valve (6).

Abstract: The present invention provides an internal shape of a rotor for a two-bore rotary carburetor used in a stratified scavenging engine whereby an engine for a power saw, lawn mower, or the like can be stabilized in the course of a complete change in orientation during idling. A groove pocket (10) in communication with a fuel supply-side bore (8) is formed at the aperture edge of each of the upstream end and the downstream end of a carburetor rotor valve (6) toward an accelerated rotation direction in the fuel supply-side bore (8) of the rotor valve (6). The groove pocket (10) is shaped so as to gradually rise and decrease in cross-sectional surface area toward the accelerated rotation direction along a peripheral surface of the rotor valve (6).

Abstract: A carburetor for a stratified scavenging two-cycle engine, in which a throttle valve and a air valve are formed in a valve element that is a single cylindrical member in which a throttle through-hole and an air through-hole are diametrically formed and which is rotatably fitted in a body, the mixture passage and the air passage being formed piercing through a body, wherein the height of the body is decreased so as to miniaturize the carburetor as a whole, and the mixture passage (6) and the air passage (9) are formed in a single cylindrical common hole (69) in which the mixture passage (6) and the air passage (9) are partitioned by a partition wall (68).

Abstract: A carburetor of a remote control model has a main body axially bored with an axial hole that is installed with a throttle and a second needle in its one side and provided with a female-threaded section formed at a certain portion of its other side for engaging with a male-threaded section of an adjustment valve. The adjustment valve possesses a fuel entering passage formed axially with a dead end, and an injection nozzle formed at the end corresponding to and for a needle valve of the second needle to move to and fro therein. And, the adjustment valve is directly installed in the axial hole without being accompanied with other components, effective to lower progressive tolerance between the injection nozzle and the needle valve to provide uniform fuel injection.

Abstract: A rotary throttle valve carburetor has a start assist device with an operating member that interacts with a throttle lever of the throttle valve to axially displace the throttle valve, preferably without rotating it. The operating member may be rotated and moved linearly for selective engagement with the throttle lever by any one of a plurality of starting features generally spaced circumferentially about the operating member. Preferably, each starting feature has a face that faces axially outward with respect to the rotary axis and when in contact with the throttle lever. Each face is spaced at a different distance from the operating member axis thus selection of each will cause the operating member to contact and move the throttle lever a different distance. The different distances correspond to varying fuel enrichments that may be associated with different temperatures of an engine to be started.

Abstract: A mixer for an engine includes a base portion having an intake passage in which the air flows, a fuel passage in which the fuel flows, and a mixing space in which the fuel and the air are mixed, and an axial hole which communicates with the mixing space, a first valve having an axial portion fitted in the axial hole of the base portion and rotatable in a circumferential direction of the axial portion, a center hole which is provided in the axial portion and communicates with the axial hole, and a first opening which is provided at the axial portion and communicates with the center hole, the first opening communicable with the fuel passage, and a first drive portion for rotating the first valve in a circumferential direction thereof relative to the axial hole for changing a communicating area of the first opening with the fuel passage.

Abstract: A diaphragm carburetor for an internal combustion engine and method of assembly includes attaching an air-fuel mixing body to a fuel metering chamber assembly independent from assembling the fuel metering chamber assembly. The fuel metering chamber assembly has an upper body and a lower body attached to one another by at least one fastener with a diaphragm carried therebetween. A fuel metering chamber is defined on one side of the diaphragm and an atmospheric chamber is defined on another side of the diaphragm. Another fastener attaches the fuel metering chamber assembly to the air-fuel mixing body independently from the fastener attaching the upper and lower bodies together. Accordingly, the fuel metering chamber assembly is removable from the air-fuel mixing body without removing the fastener attaching the upper and lower bodies to one another preferably for cleaning of a fuel nozzle that when assembled projects into an air-fuel mixing passage in the mixing body.

Abstract: A carburetor for a stratified scavenging two-cycle engine, in which a throttle valve and an air valve are formed in a valve element that is a single cylinderical member in which a throttle through-hole and an air through-hole are diametrically formed and which is rotatably fitted in a body, the mixture passage and the air passage being formed piercing through a body, wherein the height of the body is decreased so as to miniaturize the carburetor as a whole, and the mixture passage (6) and the air passage (9) are formed in a single cylindrical common hole (69) in which the mixture passage (6) and the air passage (9) are partitioned by a partition wall (68).

Abstract: A versatile rotary carburetor has an idle adjustment needle, a high speed adjustment needle, and preferably an air bypass screw which are substantially parallel to one another and are axially exposed for adjustment in a substantially common direction. Preferably a cammed rotary throttle valve is seated in a body of the carburetor for rotation about and axial movement along an axis. The rotary throttle valve intersects a mixing passage in the body, and carries a through-bore that variably generally aligns to the mixing passage upon rotation of the throttle valve. The throttle valve projects axially through an external surface of the body and threadably receives the idle adjustment needle oriented concentrically to the axis.

Abstract: A rotary throttle valve carburetor includes a main body defining a mixing passage and a valve bore, and a throttle valve rotatably received in the valve bore to selectively open and close the mixing passage. The carburetor main body includes an integral throttle valve support extending radially inwardly relative to the valve bore adjacent to a first end of the valve bore and a second end of the valve bore is open. A throttle cable retaining portion may also be integrally formed with the carburetor main body.

Abstract: A carburetor has a throttle valve assembly with a cam member and cam surface internally arranged in a body of the carburetor. The cam member is carried by the throttle valve body and preferably has outwardly extending tabs for locking engagement within slots formed in the throttle valve body. The throttle valve body has a dust seal constructed from an elastomeric material. The dust seal has one end sized for a tight resilient fit about a boss extending upwardly from a cap of the carburetor, and another end sized for tight resilient fit about a shaft carried by the throttle valve body, and a mid-section expanded over a flange.

Abstract: A compact engine start device of a combustion engine rotary-type carburetor overrides normal operation of a rotary throttle valve to provide a richer mixture of fuel-and-air to start a cold engine. Rotation of a start lever of the start device activates a releasable camming interface coupler causing the throttle lever to rotate about a rotary axis and axially lift partially out of the carburetor at prescribed angular and axial distances. This provides the engine, through a fuel-and-air mixing passage, with a controlled and enriched ratio and volume of a fuel-and-air mixture. Preferably, the start lever has a projecting rod that inserts into a hole in the carburetor body for rotation about an axis orientated substantially parallel to the rotary axis.

Abstract: A carburetor including a mixture channel and an air channel that are separated from one another, wherein a fuel opening opens into the mixture channel. A throttle element is rotatable about an axis of rotation that extends transverse of the direction of flow in the mixture channel and in the air channel and extends through both channels. As a function of its position, the throttle element throttles a flow cross-section of the mixture channel and the air channel. The flow cross-section of a portion of the mixture channel and/or of the air channel has a non-circular shape in the vicinity of the throttle element.

Abstract: A rotary throttle valve carburetor includes a body having a fuel and air mixing passage and a throttle valve movable between idle and wide open positions. A valve bore is increasingly aligned with the fuel and air mixing passage as the throttle valve is moved from idle toward its wide open position. A fuel metering needle is responsive to movement of the throttle valve so that the needle moves relative to the body in response to movement of the throttle valve. A fuel nozzle extends into the valve bore, is associated with the fuel metering needle, and has a fuel ejection passage with an effective flow area controlled by movement of the fuel metering needle relative to the fuel nozzle and includes a portion with a cross-sectional area that gradually increases in the direction of fuel metering needle movement corresponding to throttle valve movement toward its wide open position.

Abstract: A four-stroke combustion engine is lubricated by a mixture of lubricant, fuel and air received from a rotary valve type carburetor. A cylinder of the engine houses a reciprocating piston and together they generally define a combustion chamber segregated from a generally sealed cavity which contains a mechanism for operating intake and exhaust valves communicating with the combustion chamber. Generally non-burning lubricant along with fuel-and-air enters the combustion chamber from the rotary-type carburetor and blows-by the piston into the sealed cavity through a clearance defined generally between the cylinder and piston for cooling the engine and lubricating the mechanical linkage assembly. Preferably, the sealed cavity is vented directly into a rotary throttle valve of the carburetor for controlled flow back into the engine without use of a check valve, enhanced idling characteristics of the engine and substantially reduced spit-back through the carburetor air inlet.

Abstract: An apparatus for adjusting the air-fuel ratio of a fuel mixture to be supplied to an engine. The apparatus has a pair of needle valve bodies and a pair of receptacles formed in a main body of a carburetor for receiving the needle valve bodies. Each needle valve body has a needle and a head. The needles are axially movable relative to a respective needle orifice. The needles may be axially advanced and retracted by rotating the needle valve bodies within the receptacles to respectively decrease and increase the flow of the fuel mixture around the needles and through the orifices. To prevent tampering with the needle valve body setting, the head of the needle valve body has an unconventional shape requiring a specialized tool to rotatably adjust the needle valve body. To further prevent tampering, the head is recessed with the main body of the carburetor.

Abstract: A rotary throttle valve carburetor includes an air intake passage and a throttle valve bore formed in a carburetor body, a cam disposed in the throttle valve bore, and a throttle valve disposed in the throttle valve bore so that one end engages the cam and the other end is accessible from outside the throttle valve bore for operable connection to a throttle valve lever. The carburetor may also have a cable holder with a receiving cylinder for an outer tube of a throttle valve lever cable, an insert port for an inner wire of the cable and a slit between the receiving cylinder and insert port. The slit is smaller than an end of the inner wire to prevent that end from passing through the slit. The carburetor may further include a tamper resistant fuel adjustment bolt including an anti-turning body keyed to the carburetor body and splined to the adjustment bolt after calibration of the carburetor to prevent inadvertent rotation, or user tampering with the calibrated setting.

Abstract: An accelerator for a carburetor that is linked to a throttle valve and allows a piston-type accelerator pump to be operated in a simple configuration that dispenses with a link mechanism and does not greatly enlarge the carburetor. The lower surface of a throttle valve lever (10) is provided with a cam (33) that has a circular shape centered about a throttle valve stem (8) and is configured such that the cam surface (33A) thereof faces a carburetor main body (1). An accelerator pump (25) is placed parallel to the throttle valve stem (8) and the upper end of a piston rod (28) thereof is brought into contact with the cam surface (33A). The cam (33) pushes the piston rod (28) down as the throttle valve lever (10) swings in the opening direction of the throttle valve, and the acceleration fuel in the pump chamber (29) is delivered and supplied to the suction channel (2).

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: The present invention facilitates proper control of the scavenging air and fuel-air mixture for a stratified scavenging two-cycle engine that is based on a crankcase compression/scavenging method, using any carburetor. The present invention includes a drive member, which rotates based on an accelerator operation, installed on the air valve of the air passage, wherein the drive member is movable through angular reciprocal movements. A slave member, which constantly contacts a cam provided on the drive member is installed on the throttle valve of the carburetor, and wherein the slave member is movable through linear reciprocal movements. A fuel flow-rate controlling mechanism works in cooperation with these linear reciprocal movements.

Abstract: A rotary throttle valve carburetor includes a body having a fuel and air mixing passage and a throttle valve moveable between idle and wide open positions. A valve bore is increasingly aligned with the fuel and air mixing passage as the throttle valve is moved from idle toward its wide open position. A fuel metering needle is responsive to movement of the throttle valve so that the needle moves relative to the body in response to movement of the throttle valve. A fuel nozzle extends into the valve bore, is associated with the fuel metering needle, and has a fuel ejection passage with an effective flow area controlled by movement of the fuel metering needle relative to the fuel nozzle and includes a portion with a cross-sectional area that gradually increases in the direction of fuel metering needle movement corresponding to throttle valve movement toward its wide open position.

Abstract: A rotary throttle valve carburetor has a fuel-and-air mixing passage which extends through a carburetor body. A cylindrical throttle chamber extends down from a top surface of the body and communicates transversely with the fuel-and-air mixing passage. A rotary throttle seats rotatably and vertically or axially movable within the chamber and through the fuel-and-air mixing passage. The rotary throttle has a bore fully communicating and longitudinally aligned with the fuel-and-air mixing passage at wide-open throttle. The rotary throttle has a throttle shaft projecting upward through the top surface of the carburetor body and through a hole of a base portion of a plastic lid plate engaged between the top surface and a metallic bracket. An upward projecting annular shoulder of the lid plate is disposed concentrically to and spaced radially apart from the throttle shaft.

Abstract: The present invention facilitates proper control of the scavenging air and fuel-air mixture for a stratified scavenging two-cycle engine that is based on a crankcase compression/scavenging method, using any carburetor. The present invention includes a drive member, which rotates based on an accelerator operation, installed on the air valve of the air passage, wherein the drive member is movable through angular reciprocal movements. A slave member, which constantly contacts a cam provided on the drive member is installed on the throttle valve of the carburetor, and wherein the slave member is movable through linear reciprocal movements. A fuel flow-rate controlling mechanism works in cooperation with these linear reciprocal movements.

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: An accelerator for a carburetor that is linked to a throttle valve and allows a piston-type accelerator pump to be operated in a simple configuration that dispenses with a link mechanism and does not greatly enlarge the carburetor. The lower surface of a throttle valve lever 10 is provided with a cam 33 that has a circular shape centered about a throttle valve stem 8 and is configured such that the cam surface 33A thereof faces a carburetor main body 1. An accelerator pump 25 is placed parallel to the throttle valve stem 8 and the upper end of a piston rod 28 thereof is brought into contact with the cam surface 33A. The cam 33 pushes the piston rod 28 down as the throttle valve lever 10 swings in the opening direction of the throttle valve, and the acceleration fuel in the pump chamber 29 is delivered and supplied to the suction channel 2.

Abstract: A variable venturi carburetor for a combustion engine has an uprighted cup-shaped piston head which forms an integral part of a venturi within a fuel-and-air mixing passage carried by a carburetor body, and a needle that projects rigidly downward from the head into a fuel feed passage. The position of the piston head controls air flow by adjusting the air flow cross-section of the variable venturi, and the needle simultaneously controls fuel flow into the fuel-and-air mixing passage at the venturi via obstruction of the fuel feed passage. The piston head and needle move in unison by a flexible diaphragm engaged to and disposed above the head. An atmospheric chamber is defined below the diaphragm and a vacuum chamber is defined generally above the diaphragm. A vacuum passage extends through the bottom of the head communicating between the fuel-and-air mixing passage at the venturi and the vacuum chamber.

Abstract: Method of and mechanism for regulating fuel feed from a rotary valve type carburetor to an associated engine. A carburetor bypass air passage variably communicates the throttle valve hole with a bypass air source at engine idle setting of the throttle valve. The bypass air passage outlet is closed by movement of the throttle valve out of idle setting toward high speed. At an initial carburetor-to-engine set-up and calibration, a bypass regulating valve is maintained open while the engine is running at idle speed. Then the fuel-regulating needle is adjusted to maximum fuel to air (F/A) mixture ratio permitted by applicable engine exhaust quality regulations, and then is permanently set and sealed. During subsequent end user operation of the engine, the bypass valve is closed only when preparing to crank the engine for starting to thereby provide an enriched fuel-to-air mixture for starting of the engine. When the engine is running under its own power the bypass valve is maintained open.

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: Method of and mechanism for regulating fuel feed from a rotary valve type carburetor to an associated engine. A carburetor bypass air passage variably communicates the throttle valve hole with a bypass air source at engine idle setting of the throttle valve. The bypass air passage outlet is closed by movement of the throttle valve out of idle setting toward high speed. At an initial carburetor-to-engine set-up and calibration, a bypass regulating valve is maintained open while the engine is running at idle speed. Then the fuel-regulating needle is adjusted to maximum fuel to air (F/A) mixture ratio permitted by applicable engine exhaust quality regulations, and then is permanently set and sealed. During subsequent end user operation of the engine, the bypass valve is closed only when preparing to crank the engine for starting to thereby provide an enriched fuel-to-air mixture for starting of the engine. When the engine is running under its own power the bypass valve is maintained open.

Abstract: An acceleration device of a carburetor for a two cycle engine with a rotary dual valve which controls air flow through both a scavenging passage and a separate air intake passage each extending through a carburetor body. The carburetor body houses a metering fuel chamber and an air reference chamber defined by a diaphragm between them. Fuel in the metering fuel chamber is discharged through a port into the air intake passage. An acceleration pump has an actuation chamber which communicates with the scavenging passage and a pump chamber which communicates with the air reference chamber and a membrane between them. During engine acceleration the membrane is displaced by a pressure introduced into the actuation chamber to forcibly send air into the air reference chamber from the pump chamber to move, the diaphragm into the metering fuel chamber, and thereby increase the fuel delivered to the air intake passage.

Abstract: A rotary throttle valve carburetor for a two cycle engine reroutes a portion of intake air and introduces the air around the circumference of a fuel feed tube. A rotary throttle, rotatable and vertically moveable, fits into a cylindrical chamber intersecting an air intake channel through a carburetor body. A needle supported by the rotary throttle fits into the fuel feed tube which extends from a fuel metering chamber within the carburetor body into a throttling bore extending laterally through the rotary throttle. An intake portion of the air intake channel expands conically toward an upstream side. An air guide tube is aligned co-axially and radially outward from a fuel feed tube forming an air passageway there between. The intake air portion flows through the air passage from the intake portion of the air intake channel and into a bottom space of the cylindrical chamber beneath the rotary throttle.

Abstract: A rotary throttle valve type carburetor including an air intake passage extending through a carburetor body, a cylindrical valve chamber formed perpendicularly to the air intake passage, a throttle valve inserted into the valve chamber, and a throttle valve lever which rotates to impart rotation and axial movement to the throttle valve to thereby regulate the amount of air and fuel drawn through the carburetor. A plurality of circumferentially extending cam surfaces are formed on a bottom face of the throttle valve symmetrical with respect to the axis of the throttle valve, while tapered bores for receiving balls which are adapted to engage with the cam surfaces are formed in a bottom face of the valve chamber. The sliding engagement between the cam surfaces and balls due to rotation of the throttle valve is adapted to provide a predetermined axial movement of the throttle valve.

Abstract: For a four-stroke engine, a carburetor with a fuel pump diaphragm which defines a fuel pump chamber on one side and a pressure pulse chamber on its other side in communication with the engine to receive pressure pulses which actuate the fuel pump diaphragm to draw fuel into the carburetor and to discharge fuel under pressure to a downstream fuel metering assembly. An air passage communicates an air supply with the pressure pulse chamber to provide an air flow within the pressure pulse chamber which sweeps away, dries out or aerates and removes any liquid fuel within the pressure pulse chamber to avoid puddling of liquid fuel therein. In one form, a throttle valve carried by the carburetor body for movement between idle and wide open positions also actuates a valve which controls the flow of fluid through the air passage as a function of the position of the throttle valve.

Abstract: A circuit for delivering fuel into a valve chamber of a rotary throttle valve type carburetor. The fuel delivery circuit includes a fuel supply nozzle, protruding into the valve chamber and fixed at the bottom of the valve chamber to the carburetor body, and an intermediate wall. The intermediate wall is connected to the bottom of the carburetor body. The intermediate wall has a first chamber defined therein, a second chamber defined therein, and structure which cooperatively defines a first passage and a second passage therein. The first passage communicates the first chamber to the fixed end of the fuel supply nozzle, and the second passage communicates the second chamber to the first chamber. In addition, the fuel delivery circuit also includes an enclosure having a pressurized fuel chamber disposed under the intermediate wall, wherein the intermediate wall cooperatively defines a third passage that communicates the pressurized fuel chamber to the second chamber.

Abstract: A throttle valve lever for controlling the rate of fuel flow in a rotary throttle valve type carburetor is proposed, wherein the throttle valve lever has increased stiffness to help prevent structural deformation due to excessive force exerted and applied to the lever over time. The throttle valve lever basically includes an oblong structure comprising synthetic resin and an oblong reinforcement plate comprising metal. The resin structure has a hole defined therethrough, which is capable of fitting around the shaft of a throttle valve of a carburetor, and also has a lever portion at one end of the resin structure. The metal plate has a hole defined therethrough, which is capable of fitting around the shaft of a throttle valve of a carburetor, and also has a lever portion at one end of the metal plate.

Abstract: A valve opening mechanism for a rotary throttle valve type carburetor having a lever which transmits the accelerator operation to the throttle valve. The lever and throttle valve are turned while the throttle valve is simultaneously caused to move in the central axial direction from the idle position by a cam part. This movement slightly increases the degree of overlap between a throttle orifice in the throttle valve and an air intake passage in the carburetor body, and slightly reduces the depth of insertion of a metering needle into the fuel nozzle. As a result, the amount of air and fuel is increased to an amount necessary for low-temperature starting. In operation, the cam part engages with the lever and is fixed in the operative position. Then, the lever is released by the normal operation of the accelerator, and is returned to the inoperative position by a return spring.