1998 Mercury 9.9/15HP 4-stroke outboards factory service manual, Page 306Get this manual
BIG FOOT
Shift Shaft
1Pull shift shaft assembly from gear housing2Remove and replace outer O-ring from shift shaft retainer
a-Shift Shaft b-Boot c-Retainer d-O-ring (outer) e-O-ring (inner) f-Washer
g-Spring h-Washer i-Roll Pin j-Driver Pin k-Shift Cam