Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 222Get this manual
GEAR HOUSING
IMPORTANT: Both gear housing and outboard shift lever must be shifted into reverse when installing gear housing to enable the shift shaft to align with clamp3Shift 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 reverse5Lubricate splines of drive shaft with 2-4-C wTeflon 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 out thru grommet in driveshaft housing which operates reverse lock hookcSeal of water pump housing with water tube7Secure gear housing to driveshaft housing using bolts and flat washersTorque bolts to 70 lb-in(8 Nm)