Abstract: In one form, a carburetor may include an air passage, a fuel and air mixing passage, a throttle valve, an air valve and a lost motion coupler interconnecting the air valve and the throttle valve. The throttle valve may be disposed in communication with the fuel and air mixing passage and moveable between an idle position and an open position permitting an at least somewhat less restricted fluid flow therethrough than when the throttle valve is in the idle position. The air valve may be disposed in communication with the air passage, and moveable between closed and fully open positions to control air flow through the air passage.

Abstract: A fuel pump assembly may include a housing and a fuel pump within a fuel pump cavity. The fuel pump may include a motor, a pumping element driven for rotation by the motor, a pump body that maintains the position of the pumping element relative to the motor and the housing, and a flexible seal. The seal may be disposed between the pump body and the housing to provide a fluid tight seal between them. A portion of the seal may be disposed radially outwardly of a distal end of the pump body to radially position the pump body within the fuel pump cavity and a portion of the seal may be disposed axially outwardly of the distal end of the pump body to axially position the pump body within the fuel pump cavity.

Abstract: 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. The assembly may also include a purge valve that prevents fluid from being discharged from the purge prime pump through the purge passage, and a return valve that prevents fluid in the return passage from being drawn into the purge and prime pump.

Abstract: In at least some implementations, a valve for a carburetor that is moveable between open and closed positions includes a first valve portion adapted to at least substantially inhibit a first fluid flow in the carburetor when the valve is closed and a second valve portion associated with the first valve portion to at least substantially inhibit a second fluid flow in the carburetor when the valve is closed. In this way, two fluid flows may be at least substantially inhibited at the same time by the valve. In some forms, the fluid flows may include a primary fluid flow to an engine and a secondary fluid flow, such as from an accelerator pump, to the engine.

Abstract: A rotary position sensor for determining the rotary position of a rotary component may include a sensor and a magnet. The sensor may be responsive to a characteristic of a magnetic field that changes as the magnetic field moves. The magnet may be carried by the rotary component for rotation with the rotary component. A buffer may be provided around the magnet to limit distortion of the magnet field. The buffer is effective against objects normally located in the area of a device with which the sensor is used (e.g. adjacent components) as well as against foreign objects not normally in the area of the device.

Abstract: A control circuit for use with an ignition system of a light-duty combustion engine. In one embodiment, the control circuit includes a charging circuit, a timing circuit and a shut down circuit that includes a manual stop switch. Activation of the manual stop switch causes the control circuit to shut down the engine, and can do so even if the manual stop switch is only momentarily engaged by the operator.

Abstract: A seal for an air valve having a valve shaft rotatably carried in a bore formed in a body and a valve head carried by the valve shaft to control air flow through an air passage as the valve shaft is rotated. The seal may include a pair of spaced apart sealing members adapted to engage the body within the air passage to seal a junction between the valve and air passage. The seal may also include an intermediate member between and interconnecting the sealing members, where the intermediate member is flexible to permit movement of at least a portion of the sealing members toward each other and the intermediate member is also resilient to yieldably bias the sealing members away from each other at least when the sealing members are displaced toward each other.

Abstract: An engine system may include a fuel and air supply circuit and an exhaust circuit, a temperature sensor mounted on an exterior of the engine and an oxygen sensor located in the exhaust circuit. The fuel and air supply circuit may include a throttle body mounted on the engine and having a throttle valve to control the flow rate of air delivered to the engine, a fuel injector carried by the throttle body to deliver fuel to the engine and a fuel rail carried by at least one of the throttle body and the fuel injector and having an input to receive a supply of fuel and an outlet through which fuel is routed to the fuel injector. An engine control unit may be communicated with these components to control the fuel and air mixture provided to the engine as a function of the temperature and oxygen sensor outputs.

Abstract: A fuel and air charge forming device, such as a carburetor, may include a main body, a fuel and air mixing passage in the body, a fluid passage communicating with the fuel and air mixing passage and a solenoid valve. The solenoid valve may include a coil and a valve body having a base fixed against movement and a valve head extending from the base. The valve head may be driven by the coil between a first position wherein the valve head at least partially obstructs the fluid passage and a second position wherein the valve head permits greater fluid flow in the fluid passage to control fluid flow through the fluid passage.

Abstract: A carburetor valve and limiter cap assembly for limiting adjustment of fuel flow in a carburetor may include a needle valve and a limiter cap. The needle valve may have a tip, a threaded portion, a head having a flange with an outer diameter greater than the rest of the head, and one or more serrations formed on the head. The limiter cap may have a sidewall, a tab extending outwardly from the sidewall, a first cavity having an inner diameter sized for an interference fit with the flange, and at least one driving feature to engage at least one serration so that rotation of the limiter cap causes rotation of the needle valve. The interference fit between the flange and the limiter cap inhibits removal of the limiter cap from the needle valve to prevent undesired adjustment of the needle valves by an end user.

Abstract: An adjustment limiting device for a carburetor including a fuel adjustment valve rotatable to adjust a supply of fuel in or delivered from the carburetor includes an adjustment limiting cap and a connector. The adjustment limiting cap is adapted to be disposed over a portion of the fuel adjustment valve and includes a rotary connection feature adapted to limit relative rotational movement between the adjustment limiting cap and the fuel adjustment valve, and a rotation limiter to limit rotational movement of the adjustment limiting cap. The connector may be carried by the adjustment limiting cap to maintain the adjustment limiting cap on the fuel adjustment valve. The connector may be concealed by the carburetor body, permit the adjustment limiting cap to be fitted onto the fuel adjustment valve, and prevent the adjustment limiting cap from being removed from the fuel adjustment limiting valve.

Abstract: A scavenging valve assembly is used in a carburetor. The valve assembly includes a throttle valve and a rotary air valve. The throttle valve opens and closes an air-fuel passage. The rotary air valve opens and closes an air passage and has one or more air bore(s). When the rotary air valve begins to rotate, airflow travels through the bore(s) and the size of an opening area that airflow travels through continuously increases in size.

Abstract: A method, fuel system, and components for facilitating the delivery of liquid fuel from a fuel tank in fluid communication with a float bowl carburetor of an internal combustion engine, wherein evaporative emissions of the fuel from the fuel tank and float bowl carburetor are mitigated. During operation of the engine, fluid communication is permitted between the fuel tank and the carburetor, and fuel vapors at a predetermined threshold superatmospheric pressure are permitted to vent outwardly from the fuel tank. During inoperation of the engine, fluid communication is prevented between the fuel tank and the carburetor, and fuel vapors at a predetermined threshold superatmospheric pressure are permitted to vent outwardly from the fuel tank.

Abstract: In one form, a carburetor may include an air passage, a fuel and air mixing passage, a throttle valve, an air valve and a lost motion coupler interconnecting the air valve and the throttle valve. The throttle valve may be disposed in communication with the fuel and air mixing passage and moveable between an idle position and an open position permitting an at least somewhat less restricted fluid flow therethrough than when the throttle valve is in the idle position. The air valve may be disposed in communication with the air passage, and moveable between closed and fully open positions to control air flow through the air passage.

Abstract: A carburetor valve and limiter cap assembly for limiting adjustment of fuel flow in a carburetor may include a needle valve and a limiter cap. The needle valve may have a tip, a threaded portion, a head having a flange with an outer diameter greater than the rest of the head, and one or more serrations formed on the head. The limiter cap may have a sidewall, a tab extending outwardly from the sidewall, a first cavity having an inner diameter sized for an interference fit with the flange, and at least one driving feature to engage at least one serration so that rotation of the limiter cap causes rotation of the needle valve. The interference fit between the flange and the limiter cap inhibits removal of the limiter cap from the needle valve to prevent undesired adjustment of the needle valves by an end user.

Abstract: A system for managing ignition of a light-duty internal combustion engine during starting includes a charge winding used to create an ignition pulse; a first signal generated by the charge winding that indicates the speed of an engine; a second signal generated by the charge winding that indicates a piston position of the engine; a switch coupled to the charge winding for controlling the ignition pulse; and a processing device that receives the first signal and the second signal, wherein the processing device activates the switch when a comparison of the received first signal and second signal indicates that a piston is positioned at approximately top dead center (TDC).

Abstract: A starting system for a combustion engine including a carburetor with a throttle valve moveable between idle and wide open positions, a throttle control to control movement of the throttle valve during normal operation of the engine, and a linkage between the throttle control and the throttle valve. The starting system includes a recoil pulley, a pull-cord to rotate the recoil pulley, an actuator moveable in response to rotation of the recoil pulley, and a throttle override device. The throttle override device has a first control member moveable from a first position to a second position in response to movement of the actuator, and a second control member moveable in response to movement of the first control member from a first to a second position. The second control member is operably associated with the linkage to prevent the throttle valve from being in its wide open position when the second control member is in its second position.

Abstract: Supply of supplementary fuel is controlled by activation of a valve in response to certain engine operating conditions or parameters. For example, the supplementary fuel may be supplied to facilitate starting and warming up a cold engine, or to cool and/or slow down an engine operating above a threshold speed.

Abstract: A carburetor includes a main body defining a bore, a main passage and a venturi defined within the bore, and a fuel nozzle carried by the main body and including a fuel nozzle outlet communicating with the venturi. The carburetor may also include a valve member translatable across an axis of the bore, such that in a closed state, the valve member closes the main passage but maintains the venturi at least partially open. The carburetor may also include a needle valve disposed at an end of the fuel nozzle substantially opposite of the fuel nozzle outlet to variably control flow of fuel into a fuel nozzle inlet, and a needle valve transmission may be coupled between a throttle shaft and the needle valve to convert rotation of the throttle shaft to translation of the needle valve.

Abstract: A control circuit for use with an ignition system of a light-duty combustion engine. In one embodiment, the control circuit includes a charging circuit, a timing circuit and a shut down circuit that includes a manual stop switch. Activation of the manual stop switch causes the control circuit to shut down the engine, and can do so even if the manual stop switch is only momentarily engaged by the operator.