In at least some implementations, a charge forming device for a combustion engine includes a housing, a throttle valve and a vent valve. The housing has an inlet chamber in which a supply of fuel is received, a vent passage communicating with the inlet chamber and a throttle bore with an inlet through which air is received. The throttle valve is carried by the housing and has a valve head movable relative to the throttle bore to control fluid flow through the throttle bore. And the vent valve is electrically actuated, carried by the housing and has a valve element that is movable between an open position wherein fluid may flow from the inlet chamber through the vent passage and a closed position where fluid is prevented or inhibited from flowing out of the inlet chamber through the vent passage.

In at least some implementations, a charge forming device for a combustion engine includes a housing, a throttle valve and a vent valve. The housing has an inlet chamber in which a supply of fuel is received, a vent passage communicating with the inlet chamber and a throttle bore with an inlet through which air is received. The throttle valve is carried by the housing and has a valve head movable relative to the throttle bore to control fluid flow through the throttle bore. And the vent valve is electrically actuated, carried by the housing and has a valve element that is movable between an open position wherein fluid may flow from the inlet chamber through the vent passage and a closed position where fluid is prevented or inhibited from flowing out of the inlet chamber through the vent passage.

A carburetor fuel flow control device having an elongate annular body received in a cavity with an inlet in its side-wall communicating with a fuel supply passage and an outlet downstream of the inlet and adjacent to an end of the body, and a needle valve with a metering portion adjacent one end rotatably and slidably received in the body with the metering portion at least partially lapping or blocking the inlet to change the effective flow area of the inlet in response to generally axial movement of the needle valve relative to the inlet.

A carburetor fuel flow control device having an elongate annular body received in a cavity with an inlet in its side-wall communicating with a fuel supply passage and an outlet downstream of the inlet and adjacent to an end of the body, and a needle valve with a metering portion adjacent one end rotatably and slidably received in the body with the metering portion at least partially lapping or blocking the inlet to change the effective flow area of the inlet in response to generally axial movement of the needle valve relative to the inlet.

In at least some implementations, a charge forming device for a combustion engine includes a housing, a throttle valve and a vent valve. The housing has an inlet chamber in which a supply of fuel is received, a vent passage communicating with the inlet chamber and a throttle bore with an inlet through which air is received. The throttle valve is carried by the housing and has a valve head movable relative to the throttle bore to control fluid flow through the throttle bore. And the vent valve is electrically actuated, carried by the housing and has a valve element that is movable between an open position wherein fluid may flow from the inlet chamber through the vent passage and a closed position where fluid is prevented or inhibited from flowing out of the inlet chamber through the vent passage.

In at least some implementations, a charge forming device for a combustion engine includes a housing, a throttle valve and a vent valve. The housing has an inlet chamber in which a supply of fuel is received, a vent passage communicating with the inlet chamber and a throttle bore with an inlet through which air is received. The throttle valve is carried by the housing and has a valve head movable relative to the throttle bore to control fluid flow through the throttle bore. And the vent valve is electrically actuated, carried by the housing and has a valve element that is movable between an open position wherein fluid may flow from the inlet chamber through the vent passage and a closed position where fluid is prevented or inhibited from flowing out of the inlet chamber through the vent passage.

A fuel regulator includes a limit cap which is attached to a needle valve which is inserted into a regulation hole. In an inner peripheral surface of a second hole portion of the regulation hole, a restriction groove and a guide groove which extends from the restriction groove through an outer surface of a main body portion in an axial direction of the second hole portion are formed. A projecting portion which is inserted into the restriction groove is formed on an outer peripheral surface of the limit cap, and the projecting portion is capable of passing through the guide groove, and in the main body portion, a cast hole which extends from the restriction groove through the outer surface of the main body portion in a direction intersecting the axial direction of the second hole portion is formed.

A fuel regulator includes a limit cap which is attached to a needle valve which is inserted into a regulation hole. In an inner peripheral surface of a second hole portion of the regulation hole, a restriction groove and a guide groove which extends from the restriction groove through an outer surface of a main body portion in an axial direction of the second hole portion are formed. A projecting portion which is inserted into the restriction groove is formed on an outer peripheral surface of the limit cap, and the projecting portion is capable of passing through the guide groove, and in the main body portion, a cast hole which extends from the restriction groove through the outer surface of the main body portion in a direction intersecting the axial direction of the second hole portion is formed.

A needle valve body (220) has a needle hollow part (230) and a slit (232) extending in an axial direction and opened forward in a tip region. The carburetor body (B) has a body hole (202) receiving the needle valve body (220) in a longitudinally displaceable manner along an axis and a step-part circumferential edge (240a) formed in the body hole (202) and forming an orifice (250) with the slit (232) of the needle valve body (220). By operating the needle valve body (220) to adjust the size of the orifice (250), an amount of fuel supplied to a fuel discharge part (Fout) can be adjusted.

A carburetor with rotary valve includes an idle adjustment needle with an eccentric hole, accordingly a special adjustment tool used for idle adjustment needle has an eccentric boss; a carburetor with rotary valve includes an idle adjustment needle with an eccentric boss, accordingly a special adjustment tool used for idle adjustment needle has an eccentric hole. The idle adjustment needle must be cooperated with the special adjustment tool to carry out the adjustment, thus non-professional user can not casually adjust the fuel oil needle without the special tool, so that the engine can be maintained in the best setting condition to ensure the engine exhaust to meet the environmental protection requirement.