Abstract: A power tool comprising a controller for controlling the operation of the power tool wherein the controller is configured to control operation of the power tool in a default mode and in a low-noise mode, wherein; the controller, is configured to control operation of the power tool in the low-noise mode on basis of predetermined settings that are selected such that the noise output from the power tool in the low-noise mode is lower than the noise output from the power tool in the default mode.

Abstract: A choke valve structure includes an air cleaner body having a suction pipe portion provided on an end wall, a choke valve having a valve body allowed to adhere to a sealing surface formed around an opening, and a movement mechanism configured to move the choke valve along a direction parallel to the sealing surface such that the valve body moves in closing and opening directions. A blowing back prevention plate disposed on an axial line of the suction pipe portion to face the opening is provided integrally with the air cleaner body. A protrusion, allowed to come into contact with the blowing back prevention plate when the valve body moves in the closing direction, is provided on the valve body. The valve body is pressed against the sealing surface to adhere thereto when the protrusion conies into contact with the blowing back prevention plate.

Abstract: A carburetor including a one piece choke valve and shaft assembly including a shaft, a detent plate formed on a first end, a lever arm formed on a second end, a pair of opposing collars formed adjacent the detent plate and lever arm, a valve plate centrally positioned on the shaft, and opposing splines formed on the shaft enabling it to be inserted through an assembly slot cut into a shaft bore in the carburetor body. The detent plate includes a partial annular slot encompassing the angular range of travel of the choke valve. First, second and third detent pockets are formed along an outer edge of the slot. A positive positioning pin engages or interacts with the detent plate to positively position the choke valve in first, second or third angular positions corresponding to “close choke”, “half choke” and “open choke.

Abstract: In order to provide an actuating device for a choke valve of a carburetor for motorized equipment, in particular a cut-off grinder, wherein the choke valve is movable between at least a closed position and an open position by an operating element via a mechanical coupling from the operating element to the choke valve, which overcomes the disadvantages of the prior art, it is proposed that the mechanical coupling has a separating arrangement which is in operative connection with the motorized equipment such that the mechanical coupling between the operating element and the choke valve can be interrupted or respectively closed as a function of different operating states of the motorized equipment.

Abstract: A carburetor with a starting fuel supply mechanism which additionally supplies a starting fuel at the start of an engine includes a choke valve in suction passages extending through a main body; and a starting fuel supply path disposed as a bypass of a main fuel passage to connect a float chamber to the suction passages, the starting fuel supply path being provided with an opening/closing valve opened by interlocking with the closing operation of the choke valve, and a valve body of the choke valve which performs the closing operation presses valve opening/closing device while abutting on one end of the valve opening/closing device, to open the opening/closing valve of the starting fuel supply path, so that the starting fuel can be prepared to be supplied.

Abstract: A simple start diaphragm carburetor includes a carburetor body, a main adjutage, a throttle subassembly, a choke spindle, a linkage subassembly and a start fuel passage. The linkage subassembly includes a first linkage subassembly, a reset element and a second linkage subassembly which cooperates with the first eccentric element to form a linkage. When the first linkage subassembly opens the start fuel passage, the second linkage subassembly drives the main fuel supply channel to be open partially. Rotate the throttle subassembly and the choke spindle is reset by the reset element, thereby closing the start fuel passage. The simple start diaphragm carburetor can increase the probability of the successful start of an engine and keep the engine warmed-up for a long time, and reduce the burden of the user.

Abstract: A carburetor configured for use with an internal combustion engine includes a body defining a passageway therein, a throttle lever including a cam surface, and a throttle valve positioned in the passageway and responsive to movement of the throttle lever. The throttle valve is configured to rotate about a first axis from a wide-open first position to a second position at least 50 degrees from the first position. The carburetor also includes a choke lever including a follower surface configured to be engaged by the cam surface and a choke valve positioned in the passageway and responsive to movement of the choke lever. One of the cam surface and the follower surface includes an arcuate segment having a constant radius centered on a second axis. The arcuate segment is sufficiently long such that the throttle valve is configured to move at least 15 degrees while the other of the cam surface and the follower surface engages the arcuate segment.

Abstract: A carburetor comprising a one piece choke valve and shaft assembly including a shaft, a detent plate formed on a first end, a lever arm formed on a second end, a pair of opposing collars formed adjacent the detent plate and lever arm, a valve plate centrally positioned on shaft, and opposing splines formed on the shaft enabling it to be inserted through an assembly slot cut into a shaft bore in the carburetor body. The detent plate includes a partial annular slot encompassing the angular range of travel of the choke valve. First, second and third detent pockets are formed along an outer edge of the slot. A positive positioning pin engages or interacts with the detent plate to positively position the choke valve in first, second or third angular positions corresponding to “close choke”, “half choke” and “open choke.

Abstract: In an auto choke apparatus, a throttle valve and a choke valve are provided in a carburetor. A bimetal is provided near a muffler to bring the choke valve back in an opening direction after warm-up is completed. A bimetal lever has amounting hole to which one end of a choke rod is secured. A choke lever has amounting hole having a long hole shape to which the other end of the choke rod is secured. By forming the mounting hole of the choke lever in a long hole shape, the choke lever can be moved with the bimetal lever being stopped so that a throttle lever and the choke lever can be caused to work together without being restricted by the bimetal.

Abstract: A carburetor with a starter includes a carburetor body, a main fuel supply device with a swing frame, an idle speed fuel supply device with a main metering pin, a starter, a joint for a fuel input pipe and a main nozzle having a fuel nozzle. The carburetor further includes an operating mechanism having a linkage arm and an air strangler. The air strangler and the linkage arm are pivoted to two sides of the carburetor body, respectively. The linkage arm has an upper position and a lower position formed thereon. The upper position presses against the swing frame so as to move the main metering pin and cause the air strangler to shut down an air passage in the carburetor body.

Abstract: An auto choke device for an engine includes a choke valve for varying the opening of an intake passage of the engine, and a starter motor for starting the engine. Upon activation of the starter motor, the choke valve starts valve opening motion from a fully closed position. The choke valve continues the valve opening motion at a certain valve opening speed until it achieves a start opening set based on the temperature of the engine.

Abstract: A simple start diaphragm type carburetor includes a carburetor body, a main adjutage, a throttle subassembly, a choke spindle, a linkage subassembly and a start fuel passage. The carburetor body is formed to be a main fuel supply channel which includes g a gasinlet cavity, a venturi and a mixing cavity. The main adjutage is mounted on the venturi. The throttle subassembly is mounted on the carburetor body for controlling the fuel to enter the mixing cavity and the throttle spindle is pivoted to the carburetor body. The start fuel passage disposed in the carburetor body has a fuel inlet connecting with a measuring room provided in the carburetor body and a fuel outlet connecting with the mixing cavity. The linkage subassembly includes a first linkage subassembly, a reset element and a second linkage subassembly which cooperates with the first eccentric element to form a linkage.

Abstract: A carburetor assembly (1) has an intake channel section (30) and an air channel section (31). In the intake channel section (30), a throttle element and a choke element are arranged. An air control element is arranged in the air channel section (31). A first coupling unit (25) is provided which defines the position of the throttle element in at least one start position of the carburetor assembly (1). A second coupling unit (26) couples the position of the air control element in at least one operating state to the position of the throttle element. To ensure a reliable start, the choke element is held in at least one start position by the first coupling unit (25) and the second coupling unit (26).

Abstract: A carburetor assembly includes a carburetor (9) wherein a section of an intake channel (10) is configured. A throttle element and a choke element are pivotally journalled in this intake channel (10). A first coupling element is fixedly connected to the throttle element so as to pivot therewith and a second coupling element is fixedly connected to the choke element so as to pivot therewith. The first and second coupling elements form a blocking arrangement which prevents an engagement of the choke element when the throttle element is not actuated.

Abstract: The present invention relates to a carburetor of an internal combustion engine having a manually activated start position. The carburetor includes at least a choke valve and a throttle valve both located in the carburetor's main air passage which are able to move between an open and a closed position, each valve having at least one respective lever that cooperates during the manual activation to give at least one start position of the choke and throttle valves. The carburetor further usually includes at least one thermally responsive member arranged to affect the start position. Further a handle is arranged to provide a two stage draw—lift motion to attain the start position.

Abstract: A fuel supply assembly for a two-stroke crankcase scavenged combustion engine that is operated with layered scavenging is presented. The assembly includes a housing and a first and second parallel channels extending through the housing. The first channel is for a fuel/air mixture and the second channel is for auxiliary air. The assembly also includes a partition wall extending in a plane between the first and second channels and arranged upstream and downstream of at least one butterfly valve. The assembly also includes a protruding section which extends across the butterfly along the axis of rotation at least on the downstream side of the butterfly. The housing includes fuel-conveying idling ducts that open in the first channel in the region where the butterfly valve, sealing member on the partition wall, substantially contacting the protruding section at least on the downstream side of the butterfly.

Abstract: A carburettor for a two stroke engine includes a flow duct comprising rich and lean flow passages separated by a partition, at least one fuel jet communicating with the rich passage, the partition including an aperture towards which the fuel jet is directed, and a substantially planar butterfly valve being received in the aperture so as to be pivotable between a first position, in which the flow duct is substantially closed and the aperture is substantially open, and a second position, in which the flow duct is substantially open and the aperture is substantially closed, the flow duct further comprising a venturi section located substantially upstream of the aperture, and wherein the venturi section extends only partially around a perimeter of the flow duct.

Abstract: A carburetor arrangement for a manually-guided implement operated by an internal combustion engine. A carburetor supplies a fuel/air mixture to the engine, with a butterfly valve being disposed in the intake duct of the carburetor and with a choke valve being disposed upstream of the butterfly valve. A start lever is provided for actuating the carburetor in a start phase, and acts upon the choke valve. The start lever can be shifted in a direction of actuation and in an unlocking direction that is independent of the direction of actuation. The start lever can be locked in a rest position relative to the direction of actuation, and after being shifted out of the rest position in the unlocking direction is shiftable in the direction of actuation.

Abstract: A carburetor choke valve electronic control system includes: a transmission device coupled to a choke valve for opening and closing an intake path of a carburetor; an electric motor for driving the choke valve to be opened and closed via the transmission device; and an electronic control unit for controlling operation of the electric motor. The system further includes: a casing mounted on one side of the carburetor, and housing the transmission device and the electric motor; an operating lever disposed outside the casing; and a choke valve forced closure mechanism that allows the transmission device to be operated in a direction that closes the choke valve by operation of the operating lever.

Abstract: A carburetor (1) for an internal combustion engine has an intake channel section (3) wherein a throttle element and a choke element are supported to pivot about respective rotational axes (34, 35). The carburetor (1) has a starter unit which has an operating position, an off position and at least one start position. In the start position, the starter unit fixes defined positions of the throttle element and the choke element. A simple manipulability and a multifaceted operational use of the carburetor (1) are achieved when the starter unit includes an actuating lever (29, 69) and an intermediate lever (18, 68) having respective rotational axes (28, 37) which are at a distance (c) to each other at least at the elevation of the intermediate lever (18, 68) and when the actuating lever (29, 69) acts on the throttle element via the intermediate lever (18, 68).

Abstract: In an auto-choke system for a general-purpose engine, it is determined whether the operator has operated a combination switch to enable ignition in the engine and based on the result of this determination, the operation of a choke motor (actuator) is controlled to regulate the opening of the choke valve, specifically the operation of the choke motor is controlled to fully open the choke valve when ignition is found to be disabled. As a result, jetting of fuel is minimized and flooding prevented when the recoil starter is manipulated with ignition disabled. In addition, the operation of the choke motor is controlled to fully close the choke valve when ignition is found to be enabled, thereby enhancing the starting performance of the engine.

Abstract: A choke valve is controlled finely suited to the running state of an engine. A throttle valve 8 and a choke valve 9 are provided in series on an intake pipe 6, and the opening degree of the choke valve 9 is controlled by a stepping motor. The choke valve opening degree upon start of engine (start opening degree) is determined depending on the engine temperature. The stepping motor 11 is initialized at the fully closed side of the choke valve 9 when the power source for starting the engine is turned on. The start opening degree of the choke valve is judged to be closer to the fully closed side or fully opened side, and the stepping motor 11 is initialized at the fully closed side if judged to be close to the fully closed side, and at the fully opened side if at the fully opened side.

Abstract: A device for controlling a choke valve of a carburetor for an engine includes: a choke closed state hold device for holding, in a closing position, a choke lever urged by a spring in a direction for opening the choke valve, when the choke lever is turned to the closing position, the choke closed state hold device releasing the choke lever from the held state by a throttle operation thereafter performed; a control lever which turns between a low-temperature position and a high-temperature position, and which at its low-temperature position limits the position of the choke lever released from the choke closed state hold device to an intermediate position and at its high-temperature position limits the position of the choke lever to an opening position; a first control spring which urges the control lever toward the low-temperature position; and a second control spring which is made of a shape memory alloy, and which turns the control lever to the high-temperature position when the engine temperature reaches a p

Abstract: A device for controlling a choke valve of a carburetor for an engine, includes a choke closed state hold device for holding, in a closing position, a choke lever connected to the choke valve of a carburetor and urged by a spring in a direction for opening the choke valve, when the choke lever is turned to the closing position, the choke closed state hold device releasing the choke lever from the held state by a throttle operation of the carburetor after a start of the engine. The choke closed state hold device includes a lock arm provided continuously with a throttle lever and a locked arm provided continuously with the choke lever, the lock arm and the locked arm elastically surmounting each other when the choke lever is turned to the closing position in a state where the throttle lever is in the opening position corresponding to a full open position of the throttle valve, so that the lock arm prevents the locked arm from turning back.

Abstract: A vacuum-operated choke system for use with an internal combustion engine and method of using the same including a vacuum actuator for moving an actuating arm for connection to a choke valve of an internal combustion engine from a first position to a second position, an air valve in communication with the vacuum actuator, and a vacuum mechanism in communication with the vacuum actuator and the air valve for causing air to discharge through the air valve whereby the vacuum actuator can move the actuating arm from the first position to the second position and whereby the air valve is operable to allow air to enter the air valve whereby the vacuum actuator can move the actuating arm from the second position to the first position.

Abstract: A self-relieving choke valve system for a carburetor of a combustion engine automatically opens a choke valve after a successful engine start up and permits the choke valve to automatically close when the engine is shut down. The self-relieving choke valve system is preferably passive in nature and preferably self contained to the carburetor. It has a vacuum motor which preferably receives a vacuum signal from a vacuum source derived from the operating engine to open the choke valve. A lost motion linkage of the self-relieving choke valve system permits the choke valve to fluctuate between a closed position and a slightly open engine start up position without any intervention by the vacuum motor while the engine is being started.

Abstract: A vacuum-operated choke system for use with an internal combustion engine and method of using the same including a vacuum actuator for moving an actuating arm for connection to a choke valve of an internal combustion engine from a first position to a second position, an air valve in communication with the vacuum actuator, and a vacuum mechanism in communication with the vacuum actuator and the air valve for causing air to discharge through the air valve whereby the vacuum actuator can move the actuating arm from the first position to the second position and whereby the air valve is operable to allow air to enter the air valve whereby the vacuum actuator can move the actuating arm from the second position to the first position.

Abstract: A self-relieving choke adjustment apparatus for an internal combustion engine carburetor including a choke valve body and a choke mixing passage formed in the valve body. A choke plate is supported in the mixing passage for pivotal motion about a parallel choke plate axis between an open position and a closed position, such that airflow through the mixing passage tends to rotate the choke plate toward the open position. A rotary biasing element is connected between the choke plate and the choke body and applies a torque biasing the choke plate toward its closed position.

Abstract: A choke valve control system includes a choke-operating lever for opening and closing a choke valve of a carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling the opening motion of the valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring. The choke-operating lever, the choke spring and the damper are connected to the choke valve of the carburetor. In this choke valve control system, the damper includes a damper housing, a rotor, and a damper oil which is accommodated in a sealed manner in the damper housing and applies a viscosity resistance to the rotation of the rotor, which resistance increases as the viscosity increases with decreasing temperature.

Abstract: A self-relieving choke adjustment apparatus for an internal combustion engine carburetor including a choke valve body and a choke mixing passage formed in the valve body. A choke plate is supported in the mixing passage for pivotal motion about a parallel choke plate axis between an open position and a closed position, such that airflow through the mixing passage tends to rotate the choke plate toward the open position. A rotary biasing element is connected between the choke plate and the choke body and applies a torque biasing the choke plate toward its closed position.

Abstract: The invention relates to a carburetor arrangement for an internal combustion engine (1), especially for a drive motor of a work apparatus such as a motor-driven chain saw, a brushcutter, a cutoff machine or the like. The carburetor arrangement includes a carburetor (2) having an intake channel (3) and an air filter (4) mounted upstream of the intake channel (3). The air filter (4) has an air filter housing (5). The intake channel (3) opens with an intake opening (6) in a housing base (7) of the air filter housing (5). The intake opening (6) can be covered at least partially by a choke element (8). The choke element (8) is held on a choke carrier (9) so as to permit a limited movement of the choke element.

Abstract: A choke valve device in a carburetor including an opening spring for biasing a choke valve in a fully opening direction, a negative pressure operating chamber provided in a carburetor body to communicate with an intake passage at a location downstream from the choke valve, a locking piston which has a pressure-receiving face facing the negative pressure operating chamber and which is adapted to be advanced and retracted between a locked position (L) and a unlocked position (U), a locking spring for biasing the locking piston toward the locked position (L), and a locking recess which is provided in a choke lever secured to a valve stem so that the locking recess engages with the locking piston advanced to the locked position (L) when the choke lever is moved to a fully closed position (C) of the choke valve.

Abstract: A choke valve control system includes a choke-operating lever for opening and closing a choke valve of a carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling the opening motion of the valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring. The choke-operating lever, the choke spring and the damper are connected to the choke valve of the carburetor. In this choke valve control system, the damper includes a damper housing, a rotor, and a damper oil which is accommodated in a sealed manner in the damper housing and applies a viscosity resistance to the rotation of the rotor. Thus, the time required for opening the choke valve can be controlled in accordance with the level of the environmental temperature of an engine, thereby providing the stabilization of the warming operation of the engine and a reduction in fuel consumption.

Abstract: For an internal combustion engine carburetor (10) having a throttle valve (14) and a choke (22), the throttle valve (14) and the choke (22) can be brought in dependence on each other to different sets of predetermined operating positions which are appropriate respectively for the operating of the engine at no-load, for a cold start, and for a warm start, with a safe and definite adjustment being achieved in that the switch (19) is placed directly on the carburetor (10) and is connected with the choke (22) and in that the choke (22) and the throttle valve (14) are coupled with each other over mechanical couplings (16, . . . 21) with the switch (19) having a different position for each set of throttle valve and choke operating positions.

Abstract: A carburetor control system for a carburetor including a first cam and a second cam. The carburetor includes a choke valve assembly and a throttle valve assembly. The first cam is connected to the choke valve assembly. The second cam is connected to the throttle valve assembly. The second cam includes a first section and a second section. When the first cam is moved to a choke position the first section can be contacted by the first cam to latch the second cam in a start position. When the throttle valve assembly is moved to a wide open throttle position the second section can contact the first cam to hold the first cam in the choke position.

Abstract: An engine intake control mechanism has a throttle valve that can be rotated to a cold-starting position in response to the closing movement of a choke valve and, even if the throttle valve is opened beyond the cold-starting position, the choke valve is retained at the cold-starting position. Only when the throttle valve is subsequently actuated to return to its original closed position is the choke valve automatically returned to its original opened position. The engine intake control mechanism is especially useful in top handle type portable power working machines, which are subject to undesirable movements of the throttle control lever on the top handle when the engine is being started.

Abstract: A carburetor throttle and choke control mechanism incorporating a choke-throttle cold-start fast idle setting latch mechanism having, in a first embodiment, a blade of a fast idle lever specially contoured for creating upon interengagement with a tang on a throttle lever initial torque resistance to co-rotation of the fast idle lever toward latched condition and then effecting force reversal for creating aiding torque to accelerate the fast idle lever relative to choke lever and thereby open a gap in the push coupling that remains in the latched position of the choke and throttle valves. The choke lever has a relatively rigid pusher leg portion adapted for abutment in push relation with a fast idle lever tang. In a second embodiment an extension of the leg portion in the form of a generally U-shaped resilient spring hook portion is adapted to overlap the tang and releasably hook engage the same when the leg portion is brought into full push abutment with said tang.

Abstract: The invention relates to a carburetor arrangement for an internal combustion engine (1), especially for a drive motor of a work apparatus such as a motor-driven chain saw, a brushcutter, a cutoff machine or the like. The carburetor arrangement includes a carburetor (2) having an intake channel (3) and an air filter (4) mounted upstream of the intake channel (3). The air filter (4) has an air filter housing (5). The intake channel (3) opens with an intake opening (6) in a housing base (7) of the air filter housing (5). The intake opening (6) can be covered at least partially by a choke element (8). The choke element (8) is held on a choke carrier (9) so as to permit a limited movement of the choke element.

Abstract: A control mechanism for a carburetor having a throttle valve and a choke valve each having at least a cold-starting position and a full-speed position. The throttle valve is spring biased toward its third, low idle position, and the choke valve is mounted on a choke shaft and is spring biased toward its full-speed open position. When the choke valve is moved by a choke shaft lever from its open position toward its cold start closed position a fast idle lever associated with the choke valve shaft engages, via releasable latch parts, a throttle lever associated with the throttle valve. The interengaging latch parts of these fast idle and throttle levers hold both valves in their respective cold-starting positions in opposition to their respective biasing springs.