A fuel air delivery circuit, system, and method for the intake of an internal combustion engine, that provides an enhanced pressure condition to a supplementary or auxiliary air fuel circuit or circuits in connection with a conventional fuel delivery passage or passages, such as, but not limited to, a main, needle, or other jet, injector port, manifold, plenum, or the like, to provide enhanced vaporization and mixture of the fuel and air, and delivery to an associated intake path, such as the bore of a carburetor, intake runner, or the like, to provide improved throttle response and acceleration, and additionally which supplementary circuit will automatically recharge with fuel when a triggering condition is present, such as under steady state and deceleration conditions.

Methods and systems for providing vacuum to a vehicle are described. In one example, a method adjusts an engine air-fuel ratio in response to provide additional vacuum to the vehicle.

A carburetor with a throttle valve is provided in which a linkage member is in communication with the throttle valve. An idle down handle can be moved from an unactuated position to an actuated position and is in communication with the throttle valve. Movement of the idle down handle to the actuated position causes the throttle valve to be placed into the closed position. When the idle down handle is in the unactuated position the throttle linkage member can cause the throttle valve to be moved back and forth between the open and closed positions.

A carburetor with a throttle valve is provided in which a linkage member is in communication with the throttle valve. An idle down handle can be moved from an unactuated position to an actuated position and is in communication with the throttle valve. Movement of the idle down handle to the actuated position causes the throttle valve to be placed into the closed position. When the idle down handle is in the unactuated position the throttle linkage member can cause the throttle valve to be moved back and forth between the open and closed positions.

A fuel air delivery circuit, system, and method for the intake of an internal combustion engine, that provides an enhanced pressure condition to a supplementary or auxiliary air fuel circuit or circuits in connection with a conventional fuel delivery passage or passages, such as, but not limited to, a main, needle, or other jet, injector port, manifold, plenum, or the like, to provide enhanced vaporization and mixture of the fuel and air, and delivery to an associated intake path, such as the bore of a carburetor, intake runner, or the like, to provide improved throttle response and acceleration, and additionally which supplementary circuit will automatically recharge with fuel when a triggering condition is present, such as under steady state and deceleration conditions.

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.

A carburetor with a throttle valve is provided in which a linkage member is in communication with the throttle valve. An idle down handle can be moved from an unactuated position to an actuated position and is in communication with the throttle valve. Movement of the idle down handle to the actuated position causes the throttle valve to be placed into the closed position. When the idle down handle is in the unactuated position the throttle linkage member can cause the throttle valve to be moved back and forth between the open and closed positions.

A carburetor with a throttle valve is provided in which a linkage member is in communication with the throttle valve. An idle down handle can be moved from an unactuated position to an actuated position and is in communication with the throttle valve. Movement of the idle down handle to the actuated position causes the throttle valve to be placed into the closed position. When the idle down handle is in the unactuated position the throttle linkage member can cause the throttle valve to be moved back and forth between the open and closed positions.

A carburetor with a throttle valve is provided in which a linkage member is in communication with the throttle valve. An idle down handle can be moved from an unactuated position to an actuated position and is in communication with the throttle valve. Movement of the idle down handle to the actuated position causes the throttle valve to be placed into the closed position. When the idle down handle is in the unactuated position the throttle linkage member can cause the throttle valve to be moved back and forth between the open and closed positions.

A carburetor with a throttle valve is provided in which a linkage member is in communication with the throttle valve. An idle down handle can be moved from an unactuated position to an actuated position and is in communication with the throttle valve. Movement of the idle down handle to the actuated position causes the throttle valve to be placed into the closed position. When the idle down handle is in the unactuated position the throttle linkage member can cause the throttle valve to be moved back and forth between the open and closed positions.