Mercury Mariner 4, 5 102CC Sail 1990 Outboard Service Shop Manual, Page 111Get this manual
6Guide gear housing into drive shaft housing while aligning the following (3) Drive shaft sp lines with crankshaft sp lin es It may be necessary to rotate flywheel to align splines(b) Shift shaft with hole in clamp located on end of upper shift shaft and out thru opening in drive shaft housing(c) Seal of water pump housing with water tube 8Secu re upper shift shaft and lower shift shaft together using clamp (a) Tighten bolt (b) securely