the outboard motor head 40 and inboard head 42 are centrally recessed at 118 and 119 respectively to fixedly mount axially opposed low friction here ball bearings 120 fig8 and 8a the shaft 24 has reduced diameter end portions 121 and 122 which are supported for low friction rotation by the ball bearings 120 the shaft 24 between the bearings is of greater diameter than the end portions 121 and 122 and shoulders against the inner races of the bearings 120 to positively axially locate the shaft 24 with respect to the housing 16 the shaft 24 has shoulders 123 which face axially toward and abut against the rotatable inner race of each of the ball bearings 120 thus the bearings 120 handle axial and radial thrust loads of the shaft 24 and support the shaft for minimum friction rotation the bearings 120 are axially located close adjacent the opposite ends of the motor impeller 25 to rigidly rotatably support same against axial and radial dislocation the aforementioned annular plates 94 have radially outer portions which are axially fixedly trapped between oppositely axially facing steps 124 fig8 a of the motor cylinder 41 and the opposing inner ends of the bosses 45 and 46 of the outboard motor head 40 and inboard head 42 respectively the radially inboard portions of the annular plates 94 are spaced from the shaft and the bearings 120 the annular plates 94 provide a smooth surface for ends of the rotating vanes 31 to circumferentially slide against only the vanes 31 can make.