Abstract: Apparatus for venting fuel vapors present in the fuel bowl of a carburetor for an internal combustion engine. A carburetor has at least one air passage through which air is drawn into the engine, a throttle valve positioned in the air passage and movable between an open and a closed position to control the flow of air therethrough, a fuel circuit by which fuel is delivered from the fuel bowl to the air passage for mixing with air passing therethrough, and means responsive to the movement of the throttle valve for controlling the quantity of fuel delivered through the fuel circuit. A fuel bowl cover has a vent through which fuel vapors discharge when the vent is open and a valve opens and closes the vent. A fuel pump supplies fuel from the fuel bowl to the air passage as the throttle valve opens and moves the valve to a vent opening position in response to the movement of the throttle valve. The pump is actuated as the throttle valve opens whereby the valve is opened and vapors in the fuel bowl are vented.

Abstract: A carburetor improvement inhibits tampering with an idle adjustment screw after an initial adjustment of the screw is made. The improvement comprises a cover attachable to the carburetor which prevents access to the idle adjustment screw.

Abstract: A carburetor improvement comprises a flow passage through which fuel vapors created in a fuel bowl are drawn off to a chamber having a first outlet through which fuel vapors are directed to a canister and a second outlet through which fuel vapors are directed to an air passage in the carburetor. A solenoid includes a valve member movable between a first position opening the first outlet and closing the second outlet and a second position closing the first outlet and opening the chamber outlet. The valve member is moved to its first position when the engine is off so fuel vapors are collected in the canister and to its second position when the engine is operating so fuel vapors are directed to the air passage.

Abstract: Altitude compensation apparatus for use with a carburetion system for an internal combustion engine, the system having a passage through which air is drawn into the engine, a throttle valve positioned in the passage and movable between an open and a closed position to control the flow of air therethrough and a fuel circuit through which fuel is delivered to the passage for mixing with air to form an air-fuel mixture combusted in the engine. The position of the throttle valve, the flow rate of air through the passage and the vacuum level in the engine are each sensed and respective electrical signals representative thereof are supplied. The quantity of fuel supplied by the fuel circuit to the passage is metered thereby to maintain the air-fuel ratio of the mixture produced at a preselected value. In response to the aforesaid signals, the density of air being drawn into the engine is calculated and a control signal is generated to control the metering of fuel.

Abstract: Apparatus for venting fuel vapors present in the fuel bowl of a carburetor for an internal combustion engine, the carburetor having a passage through which air is drawn into the engine and a throttle valve positioned in the passage and movable between an open and a closed position to control the flow of air therethrough. The apparatus comprises an evacuable chamber and a first fluid flow path extends between the air passage and the chamber and a second fluid flow path extends between the chamber and the fuel bowl. The first fluid flow path is unblocked and the second fluid flow path is blocked when the engine is running whereby the chamber is evacuated and a vacuum is created therein and the first fluid flow path is blocked and the second fluid flow path is unblocked when the engine is not running whereby fuel vapors in the fuel bowl are drawn off to the chamber by the vacuum created therein thereby venting the fuel bowl.