Patent ID: 7794296

Claim:
A marine propulsion apparatus, that serves as a marine drive system for transmitting engine power, wherein the marine drive system comprises an elastic coupling, having an axis of rotation, with changeable property disposed between an input shaft of a marine reverse and reduction gear and a flywheel, and wherein the elastic coupling comprises an outer ring fixed to the flywheel, an inner ring engaged with the input shaft, and an elastic block held between the outer ring and the inner ring, with at least one pair of concave portions formed on the inner surface of the outer ring and the outer surface of the inner ring, the elastic block being detachably disposed on the concave portions facing each other in such a manner that one end of the elastic block fits into the concave portion of the outer ring and the other end of the elastic block fits into the concave portion of the inner ring, and having a stopping member that prevents the elastic block from slipping off and that is detachably fixed to at least one of the inner ring and the outer ring, thereby allowing a desired elastic block to be selected and incorporated to freely change the property of the elastic coupling, and further comprising at least one additional stopping member that is detachably fixed to the elastic coupling to provide stopping members lined up with each other in superimposed layers, each of said stopping members being disposed at the same end along said axis of rotation, to control the moment of inertia of the elastic coupling.