Motorized marine vehicles such as boats generally utilize an internal fuel tank. The fuel tank of the marine vehicle typically communicates with a neck or fuel conduit having an opening which opens to the exterior of the marine vehicle and through which a fuel nozzle is inserted to fill the fuel tank with fuel. A vent stack or overflow conduit may extend from the fuel tank and discharge to the side of the marine vehicle to vent fumes from the fuel tank. In the event that the fuel tank is overfilled with fuel, a visual indication of such overfilling may result from flow of fuel initially from the fuel tank through the overflow conduit and ultimately, discharge of the fuel from the overflow conduit onto the water body. However, overfilling of the fuel tank and discharge of the fuel into the water body may contribute to pollution of the water body. Furthermore, the discharged fuel may become a potential fire hazard since the fuel will float on the water and remain combustible. Additionally, air may become blocked in the overflow conduit and fuel may spill from the conduit even though the fuel tank is not full. Thus, knowledge of when to stop the flow of fuel into the fuel tank on the part of the person filling the tank to prevent tank overfilling is desirable.
Therefore, a need exists for a fuel overflow alarm system which indicates that overfilling of a fuel tank in a marine vehicle is imminent during refueling of the marine vehicle to prevent fuel from being discharged into a water body on which the marine vehicle is docked.