A self-contained marine propulsion device is disposed within a container, or pod, that is removably attachable to an undersurface of a deck of a pontoon boat. An engine is contained within the container and connected in torque transmitting relation with the marine propulsion device which can be a sterndrive device or a jet drive device. The marine propulsion system is dirigible, with a portion that is rotatable about a generally vertical steering axis and is supported by the container which is attached to the deck of the pontoon boat.