A fuel conservation device for a combustion engine includes a heat-exchanging tube disposed through a heating coil that is contained within a housing containing coolant. The heat-exchanging tube is adapted to be coupled inline with a fuel line used to supply fuel from a gas tank to a fuel management device, such as a carburetor provided by the engine. In addition, the heating coil is configured to be coupled to an exhaust pipe coupled to the engine, so as to be heated by the hot exhaust gases generated as it operates. A radiator fluidly coupled to the housing cools the coolant, so that the fuel passing through the fuel line is maintained at a temperature just below the boiling point of the fuel.