Abstract: Disclosed herein is a marine propulsion device including a gauge for indicating the vertical position of a propulsion unit relative to a boat hull attachment device and including an indicator movable in response to variation in electrical current, a circuit for supplying the gauge with electrical current, and a circular rack physically connected to one of the propulsion unit and the attachment device co-axially with the axis of vertical swinging of the propulsion unit, and a pinion in mesh with the rack and connected to the other of the propulsion unit and the attachment device and to the wiper of a potentiometer which is electrically connected to the gauge and to the current supplying circuit and which is operative to vary the electrical current supplied to the gauge in response to vertical swinging movement of the propulsion unit.