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.

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 rotary throttle valve carburetor includes a main body, a throttle valve and a fuel nozzle. The main body has a main bore with an inlet and an outlet, a valve bore that intersects the main bore and a nozzle opening that communicates with the main bore. The throttle valve has a body received at least partially within the valve bore so that the valve body rotates about an axis and moves axially relative to the main body, and a valve passage therethrough. The fuel nozzle extends through the nozzle opening and into the valve passage, and has a fuel outlet received within the valve passage, an inner surface that defines part of a fuel passage through which fuel flows in the nozzle and to the fuel outlet, and an outer surface that includes a discontinuous portion with a varying radial dimension.

In at least one implementation, a method of operating a combustion engine, includes determining a temperature equal or related to a temperature of an engine at an engine start and comparing the determined temperature to a temperature threshold, determining if an engine operating condition exceeds an engine threshold within a threshold time after the engine was started, and if the determined temperature is below the threshold temperature and the engine operating condition remains above the engine threshold and the threshold time has not passed, providing an enriched fuel and air mixture to the engine.

Provided is a starting-fuel supply device, including: a starting-fuel supply valve configured to automatically add a starting fuel to an air-fuel mixture generated by a carburetor; and a valve chamber for the starting-fuel supply valve, wherein a fuel in a fuel tank is allowed to move to an intake passage through the valve chamber for the starting-fuel supply valve with use of a manual pump configured to suck up the fuel in the fuel tank into a carburetor before start of an engine, and wherein the valve chamber is disposed at a position below the intake passage when the engine is in a stored state.

Provided is a starting-fuel supply device, including: a starting-fuel supply valve configured to automatically add a starting fuel to an air-fuel mixture generated by a carburetor; and a valve chamber for the starting-fuel supply valve, wherein a fuel in a fuel tank is allowed to move to an intake passage through the valve chamber for the starting-fuel supply valve with use of a manual pump configured to suck up the fuel in the fuel tank into a carburetor before start of an engine, and wherein the valve chamber is disposed at a position below the intake passage when the engine is in a stored state.

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.

A fuel feed unit has a base body with an intake channel section, into which a fuel opening opens. A partition wall section divides the intake channel section into a mixture channel and an air channel. The wall section has a recess in which the throttle flap at least partially lies in an end position. The wall section has, upstream of the recess, a continuous surface facing the mixture channel and which has lateral sections adjacent to the channel wall and a middle section running between the lateral sections. The lateral sections have, upstream of the throttle flap, a separation edge for the flow. In the end position, the side of the throttle flap facing the mixture channel defines a reference plane which divides the unit into a first region and a second region. The lateral sections extend, at least directly upstream of the recess, into the second region.

A fuel supply device has a housing and an intake channel section formed in the housing. At least one fuel port opens into the intake channel section. At least one fuel channel is provided and a valve with valve plate is arranged in the fuel channel. The valve has a closed position and an open position. The valve plate contacts a valve seat in the closed position. The valve plate carries out a valve stroke between open position and closed position. At least one annular gap is formed in the fuel channel. A gap width of the at least one annular gap is matched to a length of the valve stroke of the valve plate such that the gap width is not larger than twice a length of the valve stroke. A flow cross section of the annular gap is larger than a flow cross section of the valve.

A fuel supply device has a housing and an intake channel section formed in the housing. At least one fuel port opens into the intake channel section. At least one fuel channel is provided and a valve with valve plate is arranged in the fuel channel. The valve has a closed position and an open position. The valve plate contacts a valve seat in the closed position. The valve plate carries out a valve stroke between open position and closed position. At least one annular gap is formed in the fuel channel. A gap width of the at least one annular gap is matched to a length of the valve stroke of the valve plate such that the gap width is not larger than twice a length of the valve stroke. A flow cross section of the annular gap is larger than a flow cross section of the valve.