Abstract: The invention contemplates an electrical network associated with a throttle-control potentiometer whereby a standard commercially available linear potentiometer having an given angle of electrical-resistance variation may be employed, over an entire lesser angle range of throttle rotation, to provide an output voltage which, for an initial fraction of throttle displacement, is a predetermined substantially linear variation of a given input voltage, and which, for the remaining fraction of throttle displacement, remains substantially constant at the level of the upper end of the linearly varying fraction. A feature of the invention is that the slope and extent of linear variation are selectable, without modification of the linear potentiometer.

Abstract: Detonation (knock) control apparatus for an internal combustion engine, such as an outboard motor, comprises a transducer for sensing detonation and for providing a signal when detonation occurs to an electronic controller which then operates an electrically controllable valve to enrich the fuel/air mixture to the engine to thereby reduce detonation. The electronic controller is fail-safe and is responsive to loss of signal from the sensing device and to electrical power supply failure to operate the valve to enrich the mixture.