Abstract: A carburetor with a fuel and air mixing passage and a fuel delivery system may include a valve actuated by a diaphragm with no penetrations through at least the portion of the diaphragm exposed to a fuel metering chamber. The diaphragm may include at least two convolutions increasing a surface area of the portion of the diaphragm exposed to the fuel metering chamber relative to the surface area of a plane exposed to and covering the fuel metering chamber. A diaphragm may be in the form of a bellows with at least two convolutions. The diaphragm may be made of a suitable polymer or one or more pieces of a thin metal sheet or foil.

Abstract: In at least some implementations, a retainer for a fuel system component having an electrically conductive portion accessible from the exterior of the component includes a retaining feature and a grounding feature. The retaining feature is adapted to maintain the location of the fuel system component and the grounding feature electrically couples a ground wire to the electrically conductive portion of the fuel system component. The fuel system component is grounded through a path including the grounding feature and ground wire.

Abstract: A carburetor may include a body having a main bore from which a fuel and air mixture is discharged for use by an engine, a throttle valve head, a choke valve head and a flow directing feature. The throttle valve head may be carried by the body and is moveable between an idle position and a wide open position to control at least some fluid flow through the main bore. The choke valve head may also be carried by the body and is moveable between a first position and a second position to at least in part control fluid flow through the main bore. And the flow directing feature associated with the choke valve head or the throttle valve head may alter at least one of the velocity or direction of at least a portion of the fluid that flows in the main bore.

Abstract: An apparatus for delivering a fuel-air mixture to an engine is provided. The apparatus includes: a carburetor having one or more passages and one or more chambers, wherein at least some of the passages and chambers are in communication with one another; and a fluid pump communicated with the carburetor and pumping fluid into or out of the carburetor to influence an fuel-to-air ratio of a fuel and air mixture delivered from the carburetor.

Abstract: To enhance responsivity of temperature sensor detecting an engine temperature. A temperature sensor component 40 includes a metal washer 42. The temperature sensor component 40 transfers the engine temperature to a sensor body 46 via the heat transfer washer 42. A cylinder portion 8 of a cylinder block 64 has two bosses 30. The washer 42 of the temperature sensor component 40 is fixed to the boss 30 together with the electronic control unit 20.

Abstract: In at least some implementations, a carburetor includes a body, a fuel pump diaphragm and a pressure pulse passage. The fuel pump diaphragm is carried by the body and defines in part a fuel chamber on one side of the fuel pump diaphragm and a pressure pulse chamber on the other side of the fuel pump diaphragm. The pressure pulse passage communicates the pressure pulse chamber with a pressure pulse source to provide pressure pulses in the pressure pulse chamber to actuate the fuel pump diaphragm. The pressure pulse passage includes an inlet communicating with a passage in which pressure pulses are present and the inlet is spaced from a surface defining the passage in which pressure pulses are present.

Abstract: A starting system for an internal combustion engine that includes: a pump device in communication with a purging and priming circuit of a carburetor; a driven member coupled to the pump device; and a drive member rotatably carried by a recoil starter pulley of an engine. The drive member may positively drive the driven member in two directions, and the driving of the driven member may actuate the pump device.

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: An electrically conductive cover which in assembly is received over at least part of a spark plug boot and at least part of a nut portion of a metal body of a spark plug received in the boot. The cover may have an opening through which an arm portion of the boot extends which arm portion receives an electric wire for supplying a current at a high potential voltage to the spark plug.

Abstract: In at least some implementations, an engine control process includes an engine speed test and other steps. The engine speed test includes the steps of a) determining a first engine speed, b) changing the air/fuel ratio of a fuel mixture delivered to the engine, and c) determining a second engine speed after at least some of the air/fuel ratio changing event, Based at least in part on the difference between the first engine speed and the second engine speed it is determined if a change in the air/fuel ratio of the fuel mixture delivered to the engine is needed. If a change to the air/fuel ratio was indicated, the air/fuel ratio of a fuel mixture delivered to the engine is changed.

Abstract: A carburetor provides a supplemental fuel supply to an engine and includes a body, a fuel metering diaphragm and a fluid pump. The fuel metering diaphragm defines part of a fuel metering chamber and a reference chamber and has at least a portion that is movable relative to the body to increase and decrease the volume of the fuel metering chamber to control fuel flow in the fuel metering chamber. The fluid pump is carried by the carburetor or another component upstream of the carburetor and has an outlet in fluid communication with the metering reference chamber and an actuator arranged to discharge fluid through the outlet to increase the pressure within the metering reference chamber and thereby increase the fuel flow rate from the fuel metering chamber to the air-fuel passage to provide a supplemental fuel supply to the engine.

Abstract: A fuel system that in at least some implementations includes a carburetor having a fluid passage, a solenoid, a valve, a driver circuit and a control circuit. The valve may be moved by the solenoid between an open position permitting fluid flow through the fluid passage and a closed position at least partially inhibiting fluid flow through the fluid passage. The driver circuit and control circuit are communicated with the solenoid to contribute to providing power to the solenoid and controlling actuation of the solenoid. The driver circuit and control circuit provide a first magnitude of power to the solenoid to initially change the solenoid from its closed position to its open position and a second magnitude of power to maintain the solenoid in its open position wherein the second magnitude of power is less than the first magnitude.

Abstract: A solenoid valve includes a housing, a bobbin and an armature. The bobbin is received at least partially within the housing and has a body about which a coil is provided. A fluid flow path including an inlet and an outlet and a valve seat is defined by at least one of the housing or the bobbin, and the armature is moveable relative to the valve seat to control flow through the fluid flow path.

Abstract: A carburetor including a body having a main bore through which a fuel and air mixture is discharged from the carburetor for use by an engine a priming passage communicated with the main bore, a pump that moves fluid into the priming passage, and a flow restrictor received within at least a portion of the priming passage to reduce the minimum effective flow area of the priming passage. The flow restrictor has a body received at least partially within the priming passage so that fluid flows around the flow restrictor and between the structure defining the priming passage and the flow restrictor.

Abstract: In at least some implementations, a carburetor has a metering system that controls fuel flow from a fuel source to an air-fuel passage. The metering system includes a metering diaphragm sealed to a body of the carburetor to at least partly define a metering chamber between the metering diaphragm and the body, and the metering diaphragm has a continuous layer and a discontinuous layer. The continuous layer is responsive to fluid pressure within the metering chamber and moves against the discontinuous layer to open a metering valve to allow fuel flow from the fuel source and into the metering chamber when said fluid pressure is below a reference pressure.

Abstract: In at least some implementations, a seal for a wire includes a body having at least one opening adapted to receive at least one wire therethrough, and an axially extending engagement surface disposed around at least a portion of each of said at least one openings. The engagement surface has at least a portion that is not parallel to an axis of the opening and is disposed at an acute included angle relative to the axis so that, when the engagement surface is contacted by another component, the size of the adjacent opening tends to be reduced.

Abstract: To enhance responsivity of temperature sensor detecting an engine temperature. A temperature sensor component 40 includes a metal washer 42. The temperature sensor component 40 transfers the engine temperature to a sensor body 46 via the heat transfer washer 42. A cylinder portion 8 of a cylinder block 64 has two bosses 30. The washer 42 of the temperature sensor component 40 is fixed to the boss 30 together with the electronic control unit 20.

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: In at least some implementations, an apparatus includes a throttle valve rotatable between an first position and a second position, a connection member coupled to the throttle valve and a wire retainer coupled to the connection member. The connection member is adapted to be coupled to a wire that controls rotation of the throttle valve, and the wire retainer is adapted to overlie the wire and inhibit unintended decoupling of the wire from the connection member.

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.