2001 Mercury Mariner 50-60HP Factory Service Manual, Page 476Get this manual
BIGFOOT GEAR HOUSING
11Remove components from propeller shaft12Replace cam follower if worn or pitted13Replace sliding clutch if jaws are rounded or chippedRounded jaws indicate one or more of the following: Improper shift cable adjustmentEngine idle speed too high while shiftingShifting from neutral to reverse (or forward) too slowlya -Cam Follower -Metal Balls (3) -Guide Block -Spring -Sliding Clutch -Jaws
14Replace propeller shaft if any of the following exist: Splines are twisted or wornBearing surfaces of propeller shaft are pitted or wornOil seal surface is groovedShaft has noticeable "wobble" or is bent more than 0.009 in(0.228 mm)Prop shaft trueness should be measured with dial indicator with prop shaft on V-blocks51877