1995 Mariner Mercury Outboards Service Manual 50HP 4-Stroke, Page 245Get this manual
Locate Centerline Of The Outboard Locate (and mark with pencil) the vertical centerline (a) of boat transom
Installing Outboard to Boat Transom
aCenterline of Transom
NOTE: Dimensions "A& "B" and "c""0" are equal lengthIMPORTANT: During installation of dual outboards, the following is recommendedA minimum of 2212 inches (570mm) centerline to centerline width is recommendedThis is required to alleviate cowling interference during lock to lock turns if one outboard would be in the full tilt positionwhile the other outboard(s) are in the vertical running positionaMounting Bolts (4)Flat Washers (4)Locknuts (4)
Lifting Outboard
1Use lifting eye on engine and lift outboard on boat transom
DO NOT, under any circumstances, allow upper outboard mounting bolts to be closer than inch (25.4mm) from top of boat transomUpper mounting bolts must never be installed thru shims