Abstract: A fuel tank for small internal combustion engines, the fuel tank formed of a pair of lower and upper housing members which are molded from a plastic material and are sealed to one another via heat welding, for example, to define the interior volume of the fuel tank. The lower housing member includes an integral vent tube which extends substantially upwardly within the interior of the fuel tank and includes an open end. The upper housing member includes an integral baffle wall projecting downwardly therefrom which defines a baffle chamber in which the upper end of the vent tube is received. The lower housing member additionally includes an integral fitting to which a vent conduit is attached, the fitting in fluid communication with the vent tube. In use, fuel vapors are vented from the fuel tank by passing into the baffle chamber and thence into the open end of the vent tube and through the fitting and vent conduit to a carbon canister or other containment device.

Abstract: An evaporative emissions control system for small internal combustion engines. The system generally includes a charcoal canister and a carburetor with a fuel circuit shutoff valve. The charcoal canister is in fluid communication with the air space above the liquid fuel within the engine fuel tank, and optionally, with the air space above the liquid fuel within the fuel bowl of a fuel bowl-type carburetor. The charcoal canister contains charcoal media which absorbs fuel vapors when the engine is not running. During running of the engine, vacuum within the carburetor induces a flow of atmospheric air through the charcoal canister to purge the collected fuel vapors from the charcoal media, and the fuel vapors pass into the engine for consumption. The carburetor of the engine, which may be either a fuel bowl-type carburetor or a diaphragm carburetor, includes a fuel circuit shutoff valve controlled either by a vacuum signal produced within the engine or by a user-actuated mechanical linkage.

Abstract: An evaporative emissions control system for small internal combustion engines, including a charcoal canister which is in fluid communication with the air space above the liquid fuel within the carburetor of the engine and the air space above the liquid fuel within the fuel tank of the engine. The charcoal canister contains charcoal media, and when the engine is not running, fuel vapors from the carburetor and the fuel tank migrate to, and are trapped within, the charcoal media of the charcoal canister. The charcoal canister may comprise a separate component, or may be integrally formed with an engine component such as the air cleaner, the carburetor, or the body of the fuel tank, for example. During running of the engine, vacuum within the carburetor induces a flow of atmospheric air through the charcoal canister to purge the collected fuel vapors from the charcoal media, and the fuel vapors pass into the engine for consumption.