Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 271Get this manual
4Apply light coat of Quicksilver 2-4-C Marine Lubricant (92-900 18A 12) onto shift shaft splines(DO NOT use lubricant on top of shift shaft 5Shift gear housing into forward gear 11Start remaining boltsnulsand washers al front and rear of gear housingDO NOT lighten bolts or nuls at this time
a Shift Shaft (Rotate Full Counterclockwise)
Place shift lever in forward gear
a Front Mounting Locknut and Washer Locknuts and Washers (Two Each Side)