In at least some implementations, a charge forming device includes a main body having a throttle bore, a throttle valve, a housing and a circuit board including a throttle position sensor and a pressure sensor. The throttle valve is received at least partially within the valve bore, is rotatable between an idle position and a second position, and includes a magnet that is rotated when the throttle valve rotates. The housing is carried by the main body, and the circuit board is carried by the housing. A signal path is defined leading from the pressure sensor to a pressure source, the signal path includes a liquid collection area located below a gaseous area with respect to gravity.

An automatic choke device of a carburetor includes a wax attached to an engine main body, a rod configured to perform a linear motion in conjunction with expansion of the wax, a choke lever configured to rotate in conjunction with the linear motion of the rod, and a choke shaft arranged so as to be able to abut against the choke lever and connected to a choke valve of the carburetor. The choke lever includes a flat portion that engages with an engaging portion of the choke shaft, and a circular arc portion that is formed in a circular arc shape so as to be continuous from the flat portion and is brought into sliding contact with the engaging portion of the choke shaft.

A mixture formation unit has a base body in which an intake channel section is formed. The intake channel section extends from a first end side of the base body to a second end side of the base body. The mixture formation unit has at least one rectilinearly extending channel which opens into the intake channel section. The channel opens at the first end side of the base body. The mixture formation unit is preferably provided for a two stroke engine whose intake channel is divided downstream of the mixture formation unit into a mixture channel and an air channel.

A mixture formation unit has a base body in which an intake channel section is formed. The intake channel section extends from a first end side of the base body to a second end side of the base body. The mixture formation unit has at least one rectilinearly extending channel which opens into the intake channel section. The channel opens at the first end side of the base body. The mixture formation unit is preferably provided for a two stroke engine whose intake channel is divided downstream of the mixture formation unit into a mixture channel and an air channel.

In at least some implementations, a charge forming device includes a body having a main bore, a fuel metering assembly including a diaphragm that defines at least part of a fuel chamber from which fuel is provided to the main bore and a reference chamber separate from the fuel chamber, a passage communicated with a subatmospheric pressure source and with the reference chamber, and an electrically actuated valve having an open position and a closed position, and wherein the valve at least substantially prevents communication of the pressure source with the reference chamber when the valve is in the closed position and permits communication of the pressure source with the reference chamber when the valve is in the open position to vary the rate of fuel flow from the fuel chamber.

A mixture-lubricated four stroke engine has a cylinder in which a combustion chamber is formed. The combustion chamber is delimited by a piston which is mounted movably in the cylinder. The engine has an intake channel which discharges into the combustion chamber via an inlet opening controlled by an inlet valve. A mixture formation unit includes at least one fuel opening which discharges into the intake channel. For the lubrication of the crankcase interior, a flow connection connects the intake channel to the crankcase interior via a connecting opening which discharges into the intake channel downstream of the mixture formation unit. The fuel quantity is controlled by a fuel valve. A control unit is configured to activate the fuel valve in a manner dependent on the position of the crankshaft such that the fuel valve is opened at least also during a part of the compression stroke.

The present disclosure relates to a carburetor assembly (7) comprising a control unit (17), an air channel (8), a throttle valve (9), a choke valve (10), a pulsed fuel valve (11), and a fuel supply line (12). The control unit (17) is adapted to control the fuel valve (11) to supply fuel in accordance with a certain start setting, where the choke valve (10) can be open or closed. The carburetor assembly (7) comprises a rotation angle detector assembly (20) with a choke detector part (29) that is mounted to a choke shaft (30) that is connected to the choke valve (10) such that the choke detector part (29) is arranged to rotate together with the choke valve (10). The rotation angle detector assembly (20) further comprises a choke sensor device (23, 33) that is connected to the control unit (17) and can be affected by the choke detector part (29) such that the choke sensor device (23, 33) provides different output signals to the control unit (17) in dependence of whether the choke valve (10) is open or closed.

An electronic carburetor injection system is provided for an internal combustion engine. The electronic carburetor injection system is a standalone, user programmable fuel injection system that delivers additional fuel to the engine whenever a lean fuel/air mixture is delivered by a carburetor. The electronic carburetor injection system includes a fuel injector that delivers liquid fuel in the form of a spray discharge. A plate supports the fuel injector between the carburetor and an intake manifold of the engine. The plate includes an injector port that allows the spray discharge to enter the intake manifold without interfering with operating the carburetor. An engine control unit operates the fuel injector according to signals received from an oxygen sensor that is disposed within an exhaust system of the engine. During operation, the electronic carburetor injection system maintains the fuel/air mixture within a proper range across multiple driving conditions and changing environmental conditions.

An electronic carburetor injection system is provided for an internal combustion engine. The electronic carburetor injection system is a standalone, user programmable fuel injection system that delivers additional fuel to the engine whenever a lean fuel/air mixture is delivered by a carburetor. The electronic carburetor injection system includes a fuel injector that delivers liquid fuel in the form of a spray discharge. A plate supports the fuel injector between the carburetor and an intake manifold of the engine. The plate includes an injector port that allows the spray discharge to enter the intake manifold without interfering with operating the carburetor. An engine control unit operates the fuel injector according to signals received from an oxygen sensor that is disposed within an exhaust system of the engine. During operation, the electronic carburetor injection system maintains the fuel/air mixture within a proper range across multiple driving conditions and changing environmental conditions.

An attachment structure for a solenoid valve which can be stably attached to and removed from a carburetor unit with a single movement and without increasing the number of parts. A rod-like supporting portion is disposed a predetermined distance away from a surface of a carburetor unit and extending in a direction substantially perpendicular to a direction of and installed near an opening in the surface of the carburetor unit. A cylindrical engaging portion extends from a circumferential face of a cylindrical body fitted on the solenoid valve substantially perpendicular to an axial line of the rod-like supporting portion, and forms a groove-like engagement portion which is narrower in diameter than the rod-like supporting portion, whereby the engaging portion, via the groove-like engagement portion, is coupled to and supported by rod-like supporting portion when an insertion portion of the solenoid valve is inserted into the opening.