Various systems and methods are described for generating vacuum within an engine intake. A system may comprise a throttle body with a slideable throttle body and a throttle fixture with a hollow interior passage located therein.

Various systems and methods are described for generating vacuum within an engine intake. A system may comprise a throttle body with a slideable throttle body and a throttle fixture with a hollow interior passage located therein.

A dual fuel engine includes an engine operable on a gaseous fuel and a liquid fuel and has an electrical power generator. The dual fuel engine also includes a carburetor attached to an intake of the engine to mix air and fuel and connect to a gaseous fuel source and a liquid fuel source. A liquid fuel cut-off connects to the carburetor to selectively interrupt a flow of liquid fuel to the engine. The liquid fuel cut-off is operable in open and closed states such that the liquid fuel cut-off interrupts the flow of liquid fuel when closed. The dual fuel engine also includes controller operably connected to operate the liquid fuel cut-off in the open and closed states, and the controller may be programmed to implement a delay period upon engine startup before closing the liquid fuel cut-off.

A multi-fuel engine includes an engine operable on a liquid fuel and a gaseous fuel. The multi-fuel engine also includes a liquid cutoff solenoid coupled to open and close a liquid fuel path to the engine, and a gaseous cutoff solenoid coupled to open and close a gaseous fuel source to the engine. A switch couples a power source to the liquid cutoff solenoid and the gaseous cutoff solenoid to switch between fuel sources on-the-fly during engine operation.

A multi-fuel engine includes an engine operable on a liquid fuel and a gaseous fuel. The multi-fuel engine also includes a liquid cutoff solenoid coupled to open and close a liquid fuel path to the engine, and a gaseous cutoff solenoid coupled to open and close a gaseous fuel source to the engine. A switch couples a power source to the liquid cutoff solenoid and the gaseous cutoff solenoid to switch between fuel sources on-the-fly during engine operation.

A gaseous fuel and air mixing venturi device is adapted for installation in a gaseous fuel carburetor and has a venturi body defining annular inner and outer venturi passageways which each have a throat of reduced cross-sectional area and have inlet ends in communication with an air inlet of the carburetor. A fuel inlet is configured for connection to a fuel port of the carburetor, and communicates with a plurality of fuel supply ports in the body communicating radially with the inner and outer venturi passages to mix with the air flowing in the passageways.

A gaseous fuel and air mixing venturi device is adapted for installation in a gaseous fuel carburetor and has a venturi body defining annular inner and outer venturi passageways which each have a throat of reduced cross-sectional area and have inlet ends in communication with an air inlet of the carburetor. A fuel inlet is configured for connection to a fuel port of the carburetor, and communicates with a plurality of fuel supply ports in the body communicating radially with the inner and outer venturi passages to mix with the air flowing in the passageways.

An annular discharge venturi booster assembly includes a tube, a pair of supports, and a venturi booster insert. The pair of supports are attached to and extend in opposite directions from the tube and each includes an arm and a flange insertable into a slot in venturi of a carburetor. The tube includes an annular fuel channel and one arm includes a fuel line connecting the annular fuel channel to a fuel supply. A lower portion of the tube projects beyond a bottom surface of the flanges. The venturi booster insert is inserted into the tube and suspended in a venturi of a carburetor and includes an air intake portion, a fuel feed portion that includes a plurality of orifices in communication with the annular fuel channel, and an outlet portion. The fuel feed portion includes an interior surface having a continuous curvature up to a sharp perimeter edge.

An annular discharge venturi booster assembly includes a tube, a pair of supports, and a venturi booster insert. The pair of supports are attached to and extend in opposite directions from the tube and each includes an arm and a flange insertable into a slot in venturi of a carburetor. The tube includes an annular fuel channel and one arm includes a fuel line connecting the annular fuel channel to a fuel supply. A lower portion of the tube projects beyond a bottom surface of the flanges. The venturi booster insert is inserted into the tube and suspended in a venturi of a carburetor and includes an air intake portion, a fuel feed portion that includes a plurality of orifices in communication with the annular fuel channel, and an outlet portion. The fuel feed portion includes an interior surface having a continuous curvature up to a sharp perimeter edge.