Mercury Mariner 30/40 4-Stroke Outboard Service Manual 1998, Page 483Get this manual
BIGFOOT GEAR HOUSING
9Shift gear housing into forward gear positionIn forward gear the gear housing will ratchet when propeller shaft is turned clockwiseResistance wi ll be felt when propeller shaft is rotated counterclockwise10Apply Loctite Grade 271 on threads of gear housing retaining bolts
NOTE: If, while performing Step 11, the drive shaft splines will not align with the crankshaft splines, place propeller onto propellershaft and turn it counterclockwise as the gear housing is being pushed toward drive shaft housingNOTE: During installation of gear housing, it may be necessary to move the shift block (located under cowl) slightly to align upper shift sha ft splines with shift shaft coupler splines11 Position gear housing so that the drive shaft is protruding into drive shaft housing12Move gear housing up toward drive shaft housing, while aligning upper shift shaft splines with shift shaft coupler splineswater tube with water tube sealand crank shaft splines with drive shaft splines13Install fasteners and washers (two each side)14Install locknut and washer15Torque bolls and locknut (or nuts only if applicable) to 40 Ib-ft (54.0 Nm)