these purposes the specific speed sensing means is not limiting to the present invention and can be a tachometer 50 or alternatively a hall effect gear tooth sensor associated with a gear connected to one of the rotating shafts of the engine or any type of resolver that is able to provide a signal to the engine control unit 40 that represents a speed of the engine 10 throughout the description of the preferred embodiment of the present invention the gear ratio of the transmission 16 refers to the ratio in speed between the crankshaft 70 and the propeller shaft 72 in many types of marine propulsion systems the transmission 16 is not connected directly to both the propeller shaft 72 and the crankshaft 70 but instead the propeller shaft 72 is associated with additional gearing and shafts for purposes of this description the more simplified schematic representation in fig2 is sufficient to describe the operation of the present invention fig3 shows five acceleration curves 201 205 which represent different rates of change e g u03b1 1 u03b1 4 in engine speed as a function of time the five acceleration curves show how the present invention would operate to shift from low gear to high gear under several different circumstances lines 211 212 213 and 214 represent four exemplary engine speeds i e u03c9 1 u03c9 4 that can be used in the manner described above to determine the shift points according to the operation of the present invention for example if the engine speed is between lines 211 and 212 and the acceleration is less than a predetermined limit e g u03b1 1 or u03b1 2 the present invention would cause the transmission.