Mercury Mariner 4 and 5HP 4-Stroke Outboards Service Shop Manual 1999, Page 210Get this manual
GEAR HOUSING
3Shift outboard shift lever to "Reverse 4While rotating propeller shaft, push down on shift shaft to place gear housing into "Reverse" gearPropeller shaft will not rotate more than few degrees in either direction when in reverse 5Lubricate splines of drive shaft with 2-4-C wfTeflon Marine Lubricant6Guide gear housing into driveshaft housing while aligning the followingaDriveshaft and splines into upper drive shaft seal guide tube and into crankshaft splinesIt may be necessary to rotate flywheel to align splinesbShift shaft with hole in clamp located on end of upper shift shaft and outthru grommet in driveshaft housing which operates reverse lock hookcSeal of water pump housing with water tube7Secure gear housing to driveshaft housing using bolts (d) and flat washers Torque bolts to 70 Ib-in(8 Nm)