Abstract: A liquid injection system using a novel venturi injector and a novel liquid level control chamber for use in an internal combustion engine. The injection system uses water and/or a water/alcohol mix in the preferred embodiment which is pumped from a remote liquid level tank to a liquid level control chamber. A venturi injector is positioned within the internal combustion air cleaner housing to inject predetermined amounts of liquid into the carburetor of the internal combustion engine. The rushing air within the air cleaner passing through the venturi injector causes water to be pulled into the venturi and into the throat of the carburetor from the liquid level control chamber. Control means is provided in the system to control the pump to supply more liquid to the liquid level control chamber from the remote liquid tank.