|| List of recent Buret-related patents
| Tyer carburetion process|
A means for improving prior art combined cycle combustor and/or gasifiers and/or plural thermodynamic cycle gasification systems by introducing and utilizing an auger for the continuous feeding, agitation, tumbling, advancement and discharge of heterogenous carbonaceous fuel. In addition to the aforementioned improvement, i have included provisions for fontana's water gas shift reaction utilizing refectory embedded down-tubes that convey steam and oxygen into and through the chambers fluidized bed..
|Plunger lifting mechanism of a rotary-valve gas carburetor|
A plunger lifting mechanism of a rotary-valve gas carburetor includes a carburetor body, a cam, a plunger, a torsion spring, a fixed plate, a throttle wire bracket, a main measuring needle, a sleeve and a main jet pipe. The plunger is rotatablely mounted in the carburetor body, which passes through the cam, the torsion spring and fixed plate in turn and then extends out of the carburetor body, and a top of the plunger is connected with the throttle wire bracket and then fixedly connected with the sleeve; the fixed plate is fixedly connected with the carburetor body; one end of the torsion spring is elastically suppressed by the fixed plate, and the other end of the torsion spring is elastically suppressed by protrusions on side walls of the plunger.
|Diaphragm carburetor with fuel metering compensation|
A fuel and air supply device for an engine includes a carburetor having a fuel metering assembly with a fuel metering diaphragm defining at least part of a reference chamber, a scavenging air assembly including an air passage and an air valve moveable within the passage to alter air flow through the air passage, and a reference passage. The reference passage communicates at one end with the air passage upstream of the air valve and at its other end with the reference chamber to provide a reference air signal through the reference passage to the reference chamber.
|Fuel injection system for internal combustion engine|
A kit for replacing a carburetor-based fuel delivery system for internal combustion engines with an electronic fuel injection system has an electronic control unit receiving signals from pressurization pump and a number of sensors mounted on the throttle, engine and the manifold. According to the invention, the standard manifold is replaced with the machined manifold which carries at least one fuel injector with a nozzle that can extend into an intake chamber of the engine.
|Solenoid autochoke for an engine|
A choke system for an internal combustion engine includes a carburetor having an air intake, a choke valve disposed in the air intake, and a choke lever coupled to the choke valve, wherein the choke valve is movable between a closed position and an open position, a mechanical linkage coupled to the choke lever, and a solenoid attached to the carburetor and coupled to the mechanical linkage so activation of the solenoid moves the choke valve, wherein the solenoid is activated in response to activation of a starter system of an internal combustion engine, thereby moving the choke valve via the mechanical linkage to the closed position.. .
|Carburetor for a hand-guided power tool and hand-guided power tool|
A carburetor for a hand-guided power tool has a carburetor housing and a carburetor rotor supported rotatably in the carburetor housing about an axis of rotation. A needle is disposed on the carburetor rotor and projects into a fuel opening of the carburetor.
|Four cycle engine carburetors|
Various embodiments include engine carburetors. Various embodiments provide for methods of cylinder manufacturing engines.
|Pulse generator used for a one-step starting carburetor|
A pulse generator used for a one-step starting carburetor includes a pulse chamber, a lower cover, a support and a solenoid valve. Two types of pulse are produced in the pulse chamber: the normal pulse and the crowding pulse.
|One-step starting carburetor|
A one-step starting carburetor includes a body, and a pulse generator and an oil pumping unit which are connected with the body. The oil pumping unit can produce an oil pumping function to pump fuel from an oiler to the carburetor when a flywheel of an engine is revolving.
|Method of treating incontinence|
An implant for use in the treatment of urinary incontinence includes a suburethral support and an anchor portion extending from the support portion. The support portion is operatively positionable at or distal to the bulbar urethral complex and the anchor portion is operatively extensible through the obturator foramen..
|Carburetion control system|
System for controlling the carburetion of an internal combustion engine comprising the following activities: a) starting the engine; b) determining the factor λo using any known method; c)measuring the ionization current cio; d) modifying—from outside—the factor λ by a predefined amount equivalent to Δλ bringing it to the value λ1=λo+Δλ; e) repeating the measurement of the ionization current ci1; f) calculating the value of the difference of the ionization current aλci1 equivalent to cio-ci1; g) repeating operations d. And e.
|Airflow attachment assembly for carburetor|
A carburetor attachment assembly for improved engine performance including an airflow crown and a mating air cleaner base. The air flow crown is adapted to detachably mount atop a carburetor and has a contoured intake surface that guides and directs airflow into the mouth of the carburetor.
|Deceleration fuel shut off for carbureted engines|
Fuel efficiency of small carbureted engines can be improved through the use of a fuel shut off valve that ceases fuel flow in the carburetor upon determination that the engine throttle has been closed and the engine is not at or near an idle condition.. .
|Hybrid carburetor and fuel injection assembly for an internal combustion engine|
A hybrid fuel injection and carburetor assembly for delivering a fuel and air mixture into an intake manifold of an engine is provided. The assembly includes a housing and a plurality of inserts with venturi-shaped bores to establish low pressure regions in the flow of air.
|Fuel system conversions for carburetor to electronic fuel injection systems, methods of production thereof|
An electronic fuel injection system for land vehicles, comprising: a fuel tank, at least one pump, a fuel sump, wherein the at least one pump is operatively coupled to and between the fuel tank and the sump, and an engine, wherein the engine is operatively coupled to the fuel sump. A fuel sump system for land vehicles, comprising: an inlet from a pump, wherein the pump is operatively connected to a fuel tank, a fuel pump system, a regulator operatively coupled to the fuel pump system, an outlet operatively coupled to an engine, and a float component, coupled to the inlet.
|Adjustment safeguard for a set screw on a carburetor|
An adjustment safeguard for a set screw on a carburetor includes a cap held non-rotatably on the head of the set screw. The cap is surrounded by a coaxially positioned wall sleeve fixed to the housing.
|Venturi insert for a carburetor, and carburetor, system and apparatus incorporating the same|
A venturi insert for a carburetor, and a carburetor, system and apparatus incorporating the same. In one embodiment, the invention is a carburetor for an internal combustion engine comprising: a carburetor body comprising a plurality of throttle bores extending through the carburetor body, and for each of the throttle bores a fuel delivery passage terminating at a sidewall of the throttle bore; an insert comprising a plurality of venturi tubes and a linking member connecting the venturi tubes together, each of the venturi tubes comprising a venturi passage and a fuel port for introducing fuel into the venturi passage; and the insert secured to the carburetor body so that the venturi tubes extend into the throttle bores and the fuel ports are in fluid communication with the fuel delivery passages, and the linking member is in contact with the carburetor body..
|Simple startup carburetor|
A carburetor improves the starting performance of an engine. The carburetor includes a main body, a pump oil ball and a fuel-air mixing channel which extends through the main body.
|Carburetor with integrated cable retainer|
A carburetor comprising a throttle cable housing mountable over a throttle cable and couplable to a retainer or receptacle that is an integrated part of the carburetor assembly. The throttle cable housing is configured with a molded protrusion that snaps into the retainer or receptacle on the carburetor so that once installed the throttle cable housing cannot be removed without a special tool.
|Saddle-ride type vehicle|
A saddle-ride type vehicle is capable of reducing influence of travelling wind on an open end of an air hose, thus preventing fluctuations in the internal pressure of a float chamber of a carburetor. The saddle-ride type vehicle includes a carburetor placed rearward of an engine and an air cleaner placed rearward of the carburetor.
|Air cleaner assembly|
In at least some embodiments, the present invention relates to an air cleaner having a housing portion, and a low profile rain cover having an opening on an underside of the cover to allow unfiltered air to enter into the air cleaner. Also, in at least some embodiments, the present invention relates to an air cleaner including a housing and an additional component by which the air cleaner is capable of being directly coupled to a carburetor inlet.
|Urinary incontinence treatment and devices|
A surgical implant for treating urinary incontinence by providing support to a urethra of a patient includes a suburethral support and first and second soft tissue anchors. The suburethral support is formed of a mesh and includes a folded portion formed by a fold in the mesh material, the fold extending substantially perpendicular to the longitudinal axis of the suburethral support.
|Universal carburetor work stand with user reconfigurable support stanchions|
A carburetor work stand allows the user to reconfigure the carburetor support stanchions, thereby allowing any carburetor, regardless of vintage, type, size or mounting bolt pattern, to be supported by the work stand.. .
|Urinary incontinence treatment and devices|
A surgical implant for treating urinary incontinence by providing support to a urethra of a patient includes a suburethral support portion formed of a mesh material, the suburethral support having a first end and a second end. The implant also includes first and second anchoring portions that are substantially arrow-head shaped, have apertures, and include a plurality of barbs.
|Device, system and methods for introducing soft tissue anchors|
A system for providing support to an anatomical structure of the pelvis includes first and second soft tissue anchors, a suburethral support, an introducer, and a filament. The first soft tissue anchor has a proximal end and a distal end and includes a base having a hollow tubular structure, a plurality of barbs, and a tip.
|Urinary incontinence treatment and devices|
A system for treating urinary incontinence includes a suburethral support, first and second soft tissue anchors, and an introducer. The suburethral support is formed of a mesh material, the first and second soft tissue anchors each have a tip, a base, a first face, a second face, a plurality of barbs, and an aperture extending from the first face to the second face.
|Apparatus for spray injection of liquid or gas|
An injection gate (44,144,244,344) for high pressure, high velocity secondary fluid for admixture of an atomized spray (80,180) thereof with another or primary fluid that atomizes the other fluid. The secondary fluid may be an accelerant and the primary fluid may be a low pressure fuel/air mixture in a fuel injection arrangement for an internal combustion engine.
An engine includes: a piston; a carburetor having a diaphragm fuel pump, the diaphragm fuel pump including a pump chamber configured to suck and discharge fuel and a diaphragm chamber to which a pressure to drive the pump chamber is applied; and a communicating passage configured to connect between the diaphragm chamber and a negative pressure part in which a negative pressure is created due to movement of the piston. A flowback prevention part is formed in the communicating passage to allow fluid to move only in on direction from the diaphragm chamber to the negative pressure part..
|Carburetor system for a carburetor engine|
A fuel supply system for small two-stroke internal combustion engines for e.g. Chain saws, line trimmers and similar hand-held power-tools including a diaphragm carburetor (20) equipped with a purging system (80a, 81a) or priming system (80b, 81b) for facilitating starting of the engine (1).
|Plugs for carburetors|
In accordance with one implementation, a carburetor includes a body having a fluid passage formed therein and a counterbore located along the fluid passage. The counterbore has a first sealing surface and a central axis, and the body further includes a second sealing surface located radially closer to the central axis than is the first sealing surface.
|System and method of improving fuel efficiency in vehicles using hho|
A system and method of providing hho gas to an internal combustion engine in a vehicle involves providing a liquid electrolyte solution to an hho generator configured to produce and output hho gas therefrom, separating residual electrolyte solution from the hho gas output by the hho generator, storing a quantity of the hho gas in a pressure tank at a pressure level exceeding an ambient atmospheric pressure, and regulating a rate at which the hho gas from the pressure tank flows to the internal combustion engine with a carburetor device.. .
|Carburetors for providing air-to-fuel ratio variability independent of engine load|
Carburetor features, which can include but are not limited to varying slope angles in different sections of a multi-sectioned carburetor needle, can provide combustion mixtures to an engine that include a fuel-air ratio that is variable independent of the rate of air flow through the carburetor. Related methods, systems, articles of manufacture, etc.
|Plunger valve for a propane carburetor|
A plunger valve. The plunger valve includes a body, where the length of the body is between 13 millimeters and 20 millimeters.
A fuel carburetor includes a fuel passage, a heat medium passage, a space part, and an absorbent material. Ammonia as fuel flows through the fuel passage.
|Throttle body fuel injection system with improved fuel distribution|
A throttle body fuel injection system and method that is arranged to easily replace four-barrel carburetors includes a throttle body assembly with four main bores, each with a throttle plate and an associated fuel injector. Each injector feeds fuel into a circular fuel distribution ring via a fuel injection conduit, which introduces pressurized fuel into the air stream.
|Process analysis system with sterile sampling of mechanically-sensitive material from a bioreactor|
Method for transport of suspensions containing mechanically sensitive material with a sample-transporting device comprising transport conduits and at least one system for accelerating a sample or aliquot through the transport conduit from at least two burets.. .
|Automatic choke for an engine|
An internal combustion engine includes a muffler configured to reduce exhaust gas noise. The muffler has a housing defining an interior and an exterior.
|Variable venturi and zero droop vacuum assist|
An engine includes a carburetor including a variable venturi having a fixed surface and an adjustable surface that form a constricted section, a throttle valve downstream of the variable venturi, a governor assembly including a governor configured to detect an engine speed of the engine, a governor arm coupled to the governor, the venturi, and the throttle valve, and a governor spring coupled to the governor arm to bias the throttle valve towards the fully open position, and a vacuum actuator including an actuator linkage coupled to the governor spring and also coupled to a pressure-sensitive member for movement with the pressure-sensitive member in response to an engine vacuum, and an actuator spring biasing the actuator linkage to increase the tension on the governor spring.. .
Golf ball 2 has spherical core 4, cover 6 situated on the external side of the core 4, and paint layer 8 situated on the external side of the cover 6. The cover 6 has a shore d hardness of no greater than 61.
A carburetor includes a main fuel path connected to a main nozzle and a slow fuel path connected to a slow port. The main fuel path and the slow fuel path are separated from each other and are independently communicated to a constant fuel chamber below a fuel level of the fuel chamber.
|Carburetor fuel filter|
An on-board fuel filter for a carburetor includes a filter element made from a non-metallic material. The material can be a polymeric material and may be a woven or a non-woven material.
|Fuel metering diaphragm with backing plate|
In at least some implementations, a carburetor having a fuel metering system including a diaphragm assembly that moves in response to pressure changes in a metering chamber to actuate a metering valve may include a flexible diaphragm adapted to carried by a body of the carburetor at a periphery to define part of the metering chamber. The portion of the diaphragm that defines part of the metering chamber defines a chamber projected area of the diaphragm.
|Two-stroke engine having an intake arrangement|
A two-stroke engine has an intake arrangement including a carburetor. An intake channel divides into a mixture channel and an air channel.
|Air supply device of stratified scavenging two-cycle engine|
An air supply device (1) of a stratified scavenging two-cycle engine includes: a mixture passage (40) that penetrates a carburetor (2) and an insulator (3), the mixture passage being provided by a carburetor-side mixture passage (8) and an insulator-side mixture passage (21); a air passage (41) that is provided by a carburetor-side air passage (9) and an insulator-side air passage (22); a throttle valve (13) provided in a single bore (4) of the carburetor (2), the throttle valve(13) being provided by a butterfly valve that rotates in conjunction with a throttle operation; and a flow rate regulator (28) provided inside the air passage (41), the flow-rate regulator (28) bulging inward in the air passage (41). At least a part of a periphery of a valve body (17) of the throttle valve is close to the flow-rate regulator (28) until the valve body (17) is rotated from an initial position corresponding to an idling speed at a predetermined rotation angle..
|Air supply apparatus for two-stroke combustion engine|
The present invention relates to an air supply apparatus for a two-stroke stratified scavenging combustion engine. The air supply apparatus includes an air cleaner having an air outlet and a partition, such that the partition substantially divides the air outlet into a first section and a second section.
|Engine working machine|
There is provided an engine working machine operated by an engine including a fuel tank, a carburetor and a crankcase, wherein the engine working machine is provided with a fuel supply path configured to supply an additional fuel in an interior of a crank chamber at a time of starting and an starting aid device including a solenoid valve configured to open/close the fuel supply path. The solenoid valve provided inside the starting aid device is controlled by a control unit equipped by a control circuit board and is driven by power of the battery so as to open/close a fuel inlet hole.
|Vacuum carburetor fuel drain systems and methods|
Systems and methods for draining fuel from a carburetor of a combustion engine can include a first control valve in communication between a fuel source and a fuel chamber of a carburetor and a second control valve in communication between the fuel chamber of the carburetor and a drain reservoir. The first and second control valves can be coupled and operable such that, upon disengagement of the engine, the first control valve can be closed to block a supply of fuel to the fuel chamber, and the second control valve can be opened to connect the drain reservoir to the fuel chamber, which can operate to draw liquid fuel from the fuel chamber into the drain reservoir.
|Carburetor and methods therefor|
A carburetor having an inlet opening that includes a pair of concavities operative to direct air toward the metering rod of the carburetor. A carburetor having an inlet opening that includes an arcuate manifold adjacent to the inlet opening and in fluid communication with a fuel reservoir.
|Choke override for an engine|
A choke system for an internal combustion engine includes a carburetor having a choke valve disposed in a passage; a cooling fan providing a variable air flow; an air vane moveable in response to the variable air flow; an air vane linkage coupling the air vane to the choke valve, the air vane linkage operating the choke valve by the movement of the air vane; a manually operated choke control; an override linkage coupling the choke control to the choke valve; and a thermally responsive member configured to engage the override linkage to retain the choke in a partially open position above a threshold temperature. The choke control may be moved to a first position in which the choke control overrides the thermally responsive member and the air vane linkage to maintain the choke valve in a closed position..
|Device for introducing biomaterial into a combustion or carburetor chamber|
The invention relates to a device for introducing biomaterial into a pressure-loaded combustion or carburetor chamber (1), comprising a feed apparatus (2) for feeding biomaterial to a pressure pipe (3), in which a plunger (4) is guided in such a way that the plunger can be moved back and forth against a pressure lock (5) to the combustion or carburetor chamber (1) in order to form a compressed plug (6) comprised of biomaterial, which is sealed against the combustion chamber (1) and which is periodically advanced toward the combustion chamber (1).. .
A gravity flow device for dispensing a fluid may include a gravity flow body to retain the fluid, a valve body to control the flow of the fluid, and a detachable stem to connect to the valve body. The gravity flow device may be formed from glass, and the detachable stem may be formed from plastic.
|Engine and engine working machine|
A portable engine configured to operate a working machine includes: an engine body mainly configured by a crankcase and a cylinder; a carburetor connected to an inlet port of the cylinder; an air cleaner connected to the carburetor to filter suction air; a cleaner box configured to accommodate the air cleaner; and a fuel tank configured to store fuel which is supplied to the cylinder, wherein at least a part of the fuel tank is located between the cleaner box and the engine body.. .
|Carburetor fuel supply system|
In at least some implementations a carburetor may include a main bore through which a fuel and air mixture is delivered from the carburetor, a fuel metering assembly, a supplemental fuel pump and a valve. The supplemental fuel pump includes a diaphragm that defines a fuel chamber on one side from which fuel may be discharged to at least temporarily increase the amount of fuel discharged from the carburetor and a reference chamber on the other side that is communicated with a reference pressure source.
|Pipe system and method of use|
Pipe system comprising a bowl aperture, a inhaling aperture and a carburetor aperture is disclosed. Said pipe comprising a bowl assembly having a bowl and said bowl aperture.
A carburettor including a primary air passage, an adjustable throttle valve situated within the primary air passage, a fuel supply nozzle communicating with the primary air passage and connected to a fuel metering valve for varying the amount of fuel discharged through the nozzle and a rotary input shaft adapted to be connected to an engine speed control member and which is connected to the throttle valve to move the throttle valve between open and closed positions. The rotary input shaft is also connected to a carriage to move the carriage, the carriage carrying at least one elongate inclined ramp which extends in the direction of movement of the carriage and which is engaged by a follower connected to the valve member.
|Engine and engine operating machine including the same|
An engine including: a cylinder block formed with a cylinder bore; a carburetor including, a fuel storage portion that stores fuel supplied from a fuel tank and supplies the fuel to a suction path, and a fuel discharge path that discharges fuel overflowed from the fuel storage portion; a starting fuel supply device including, a starting fuel storage chamber that is provided on a fuel route defined by the fuel tank and the carburetor and stores a predetermined amount of fuel, a fuel delivery portion that delivers the fuel to a starting fuel supply path connected to the suction path or the cylinder bore, and a fuel return path that discharges the fuel overflowed from the starting fuel storage chamber; and a notifying portion that visually notifies that the starting fuel storage chamber is filled with fuel.. .
|Carburetor float and method of manufacturing same|
A method of making a carburetor float by first creating a homogeneous mixture of gas and polymer in a plastic injection machine. The gas/polymer mixture is injected into a tool having a mold cavity.
|Carburetor air intake housing and air flow enhancing securement plate|
An air intake housing and flow enhancing plate for a carburetor with a fluted and contoured air intake opening that flushly aligns with and matches the shape of the carburetor air intake opening. The low profile plate is made of metal for durability and heat resistance.
|Method for controlling the fuel supply to an internal combustion engine at start-up and a carburetor|
The invention concerns a method for controlling the fuel supply to an internal combustion engine at start-up, the engine having a fuel supply system. The invention also concerns a carburetor having a fuel supply system including a main fuel path connecting a diaphragm controlled regulating chamber to a main outlet in the region of the venturi section, the main fuel path including an actively controlled fuel valve, and an idling fuel path branching off from the main fuel path downstream of the valve and ending in at least one idling outlet in the region of a throttle valve, the fuel supply system further including a start fuel line starting upstream or downstream of the fuel valve and ending in at least one start fuel outlet to the intake channel..
The present invention provides a diaphragm carburetor wherein heat transferred from the engine to the carburetor through the insulator is reduced to lower the temperature of the carburetor unit and reduce the occurrence of bubbles in the fuel. The carburetor of the present invention is a diaphragm carburetor in which a fuel channel that extends from a pump chamber of the carburetor to a constant-pressure fuel chamber is divided into two branches to form one branch as a main fuel channel connected to the constant-pressure fuel chamber, and the other branch as a fuel circulation channel for passing the fuel through the body side surface of the carburetor on the insulator side, or the body side surface of the insulator on the carburetor side, causing the fuel to make a circuit around the carburetor, and returning the fuel to the fuel tank..
|Carburetor fuel supply system|
A purge and prime assembly for a carburetor includes a purge and prime pump that alternately takes in and discharges fluid, and a plurality of passages through which fluid is routed. The passages may include a purge passage through which fluid is drawn by the purge and prime pump, a return passage through which fluid is discharged from the purge and prime pump and discharged from the carburetor, and a priming passage through which a portion of the fluid discharged from the purge and prime pump is routed to a main bore of the carburetor.
|Apparatus for measuring air amount of engine oil and method using the same|
An apparatus for measuring air amount of engine oil includes an inflow pipe in which the engine oil flows in connection with an engine and an inflow valve, a measuring burette having an inflow hole connected with the inflow pipe and an outflow hole formed at the other side and a measurement camera provided at the side of the measuring burette to photograph graduations, a vent pipe branched from the outflow hole of the measuring burette and a bent valve provided on the vent pipe, a drain burette having a drain pipe connected with the outflow hole provided at one side thereof and having a drain valve provided on the drain pipe, an auxiliary drain pipe having one side branched from the inflow hole and the other side connected to the drain burette and an auxiliary valve provided on the auxiliary drain pipe, and a control unit.. .
A modified carburetor allows the fuel and air input ratio to be adjusted by varying the opening sizes in the carburetor. After the proper air opening size is determined and set, the fuel jet setting can be adjusted for cold starts and/or to fine tune the engine.
|Carburetor choke mechanism|
A carburetor choke mechanism comprising: an actuator linearly expanded and contracted based on a temperature change; a connection lever which is connected to a rotation axis at one end, and rotates based on receiving a thrust of the actuator; a choke lever which is connected with the other end of the connection lever, and receives a rotatory force; and a valve shaft where a choke valve is fixed to one end thereof, and a valve shaft lever which receives a transfer of a rotatory force from the choke lever is provided on the other end thereof, wherein the choke lever has a bottomed cylindrical shape covering an outer circumference of the valve shaft lever, and the valve shaft penetrates a bottom thereof, and is provided rotatably, and a connection mechanism between the connection lever and the choke lever is provided inside a cylindrical outer periphery of the choke lever.. .
|Starting system for internal combustion engine|
A starting system for an internal combustion engine automatically operates a starting feature on a carburetor associated with the engine. The starting system includes a cam with a bearing mounted on the crankshaft.
|Carburetor including one-piece fuel-metering insert|
A carburetor includes a body having an inner wall and an air/fuel passageway. An insert includes a base having a shape that closely matches the inner wall and a first tower having a first end disposed within the air/fuel passageway.
|Air supply device for 2 stroke engine|
An air supply device (2) used in a two-stroke engine includes: an insulator (14) having an insulator mixture passage (17) that is in communication with an intake port (5a) provided in an engine body (1) of the two-stroke engine, the insulator being attached to the engine body (1); a carburetor (15) having an insulator mixture passage (17) that is in communication with an insulator mixture passage (17), the carburetor (15) being attached to the insulator (14); an air cleaner (16) having a mixture-side opening (25) that is in communication with the carburetor mixture passage (19), the air cleaner (16) being attached to the carburetor (15); an accumulating portion (29) that accumulates a blow-back fuel returned through the mixture-side opening 25, the accumulating portion (29) being provided inside the air cleaner (16); and an auxiliary passage having a base end connected to the accumulating portion (29) and a distal end connected to a portion affected by a pressure fluctuation inside a crankcase chamber provided in the engine body (1).. .