Abstract: An adaptor member for accommodating use of a desmodromic cam-actuated shifting mechanism into a conventional propeller shaft cavity formed in the lower end of the gearcase of a marine propulsion system, wherein forward thrust on the propeller shaft is transferred to the gearcase at a point aft of the forward and reverse gears mounted about the propeller shaft. The adaptor member includes a cup, which is adapted to mount the fore one of the forward and reverse gears through a bearing member. The adaptor member further includes an internal passage within which is disposed the movable cam of the shifting mechanism, and an opening is in communication with the passage for allowing connection of the shift shaft to the shifting cam after assembly of the adaptor member into the gearcase cavity.

Abstract: A bidirectional thrust bearing system for the propeller shaft of a marine propulsion system includes a substantially circumferential groove milled into the propeller shaft. A pair of substantially semicircular force transferring members are adapted for placement within the groove, and front and rear bearing collars are placed adjacent the force transferring members. Front and rear needle bearings are provided adjacent the front and rear bearing collars, respectively. A front bearing adapter, interconnected with the walls of the cavity within which the propeller shaft is disposed, transfers forward thrust in the propeller shaft to the gearcase. A rear bearing carrier, held in position by means of a ring nut mounted within the cavity, serves to transfer rearward thrust in the propeller shaft to the gearcase.