2001 Mercury Mariner 50-60HP Factory Service Manual, Page 424Get this manual
NON-BIGFOOT GEAR HOUSING
4Check bearing surfaces of propeller shaftIf shaft is wornpitted, replace shaft and corresponding bearing5Replace propeller shaft if: aSplines are twisted or wornbBearing surfaces of propeller shaft are pitted or worncOil seal surface is grooved in excess of 0.005 in(0.12mm)dShaft has noticeable "wobble" or is bent more than 0.006 in(.152 mm)Check with dial indicator and V-blocksaV-BlocksBearing SurfacesCheck with Dial Indicator Here