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.

A fuel supply device has a base body, in which an intake channel section is formed. At least one adjustable throttle element for controlling the free flow cross section of the intake channel section is provided. At least one fuel opening opens into the intake channel section. A partition wall section is arranged in the intake channel section upstream of the throttle element. The partition wall section and the throttle element divide, in a completely open position of the throttle element, the intake channel section upstream of the throttle element into a mixture channel, into which the fuel opening feeds fuel, and an air channel. In order to improve the cooling of the fuel supply device, the partition wall section has at least one element for increasing the surface area within the mixture channel.

In at least some implementations, a charge forming device for a combustion engine includes a throttle body and a throttle valve. The throttle body has a throttle bore with an inlet through which air flows into the throttle bore and an outlet from which a fuel and air mixture exits the throttle bore. The throttle bore has a throat between the inlet and outlet and the throat has a reduced flow area compared to at least one of the inlet and outlet. The throttle valve has a valve head received within the throat of the throttle bore and movable relative to the throttle body between a first position and a second position wherein the flow area between the valve head and the throttle body is greater when the valve head is in the second position than in the first position.

Disclosed is an improved rotary throttle valve carburetor with a simple structure and that can be adjusted easily, without replacing parts. The improved rotary throttle valve carburetor includes: a throttle valve having a throttle hole; a metering needle disposed perpendicularly to an air intake passage; a fuel nozzle; and a starting mechanism comprising a throttle valve lever, an operating cam, and an adjusting screw. The throttle valve lever is coupled to the rotary throttle valve and is configured to rotate the throttle valve into a first state with increased airflow for cold starting. The operating cam is configured to push the throttle valve lever upward and hold the throttle valve lever in the first state using an engaging protrusion. The adjusting screw is configured to adjust a depth of the metering needle being inserted into the throttle hole by adjusting a position of the throttle valve lever.

An improved rotary type carburetor for a stratified scavenging engine designed to enable the easy adjustment of air and fuel flow at the time of initial configuration is disclosed. The improved rotary carburetor includes an air intake passage and an air-fuel mixture passage formed in a horizontal direction on a carburetor main body. The throttle valve of the improved rotary carburetor can be fitted into a cylindrical-throttle-valve hole formed orthogonal to a fuel and an air passage of the carburetor main body. The throttle valve has the air supply side valve hole formed on the air intake passage side and a fuel supply side valve hole formed on the air-fuel mixture passage side.

An improved rotary type carburetor for a stratified scavenging engine designed to enable the easy adjustment of air and fuel flow at the time of initial configuration is disclosed. The improved rotary carburetor includes an air intake passage and an air-fuel mixture passage formed in a horizontal direction on a carburetor main body. The throttle valve of the improved rotary carburetor can be fitted into a cylindrical-throttle-valve hole formed orthogonal to a fuel and an air passage of the carburetor main body. The throttle valve has the air supply side valve hole formed on the air intake passage side and a fuel supply side valve hole formed on the air-fuel mixture passage side.

In at least some implementations, a charge forming device includes multiple throttle bores, an inlet chamber in which fuel is received, at least one fuel passage communicating the inlet chamber with the throttle bores, and a valve having an inlet in communication with the inlet chamber, an outlet and a valve head that is movable and allows flow from the inlet chamber through the outlet when the pressure in the inlet chamber is greater than a threshold pressure.

In at least some implementations, a charge forming device includes multiple throttle bores, an inlet chamber in which fuel is received, at least one fuel passage communicating the inlet chamber with the throttle bores, and a valve having an inlet in communication with the inlet chamber, an outlet and a valve head that is movable and allows flow from the inlet chamber through the outlet when the pressure in the inlet chamber is greater than a threshold pressure.

In at least some implementations, a fuel metering valve, includes a bobbin defining a passage and having one or more voids in the surface of the bobbin that defines the passage, aa wire coil around the bobbin and an armature. The armature is received within the passage in the bobbin and movable relative to the bobbin from a first position to a second position when electricity is supplied to the wire coil.

In at least some implementations, a limiter cap assembly for a carburetor having a cavity in which one or more adjustable valves are received, includes a plug adapted to be received within a cavity of the carburetor and having an opening and a cavity aligned with the opening, a clasp engageable with the plug and having at least one retention feature and an opening aligned with the opening of the plug, and a limiter cap received within the opening of the plug and engaged with the retention feature of the clasp. Removal of the limiter cap from the plug opening is prevented by engagement of the retention feature with the limiter cap and by engagement of the clasp with the plug.