2001 Mercury Mariner 50-60HP Factory Service Manual, Page 507Get this manual
BIGFOOT GEAR HOUSING
8Grasp the driveshaft pre-load tool bolt head and lightly turn drive shaft back-and-forth (no movement should be noticed at propeller shaft)9Dial Indicator registers amount of backlash, which must be between specification shown in chartMODEL 4050 Bigfoot (4-Stroke) 5060 Bigfoot (4-Stroke) 7590 (4-Stroke) 60 Bigfoot 75-thru-90 (3 Cylinder) 100115125 (4 Cylinder) DIAL INDICATOR MINIMUM 0.012 in(0.30 mm) 0.012 in(0.30 mm) 0.013 in(0.38 mm) 0.012 in(0.30 mm) 0.012 in(0.30 mm) 0.013 in(0.38 mm) READING MAXIMUM 0.019 in(.48 mm) 0.019 in(.48 mm) 0.019 in(.55 mm) 0.019 in(.48 mm) 0.019 in(.48 mm) 0.019 in(0.55 mm)
10If backlash is less than the minimum specification, remove shim(s) from in front of forward gear bearing raceIf backlash is more than the maximum specification, add shim(s) in front of forward gear bearing raceWhen reinstalling pinion nut, apply Loctite 271 on threads of nut