1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 202Get this manual
7Replace second lubricant "Vent" screw and gasketIMPORTANT: Do not lose more than one fluid ounce (30cc) of gear lubricant while reinstalling "FILL" screw8Remove lubricant tube from "Fill" hole; install "Fill" screw and gasket CAUTION
Do not misinterpret propeller shaft movement with propeller movementIf propeller and propeller shaft together move forward-and-aft, this is normal; however, propeller should not move forward-and-aft on propeller shaft7After first use, retighten propeller nut and again secure with tab washerPropeller should be checked periodically for tightness, particularly if stainless steel propeller is used
Propeller Installation
WARNING
If gear housing is not removed from drive shaft housing, before attempting to remove or install the propeller, remove (and isolate) spark plug leads from spark plugs to prevent engine from starting accidentally1Apply liberal coat of one of the following Quicksilver products on propeller shaft splines: Special Lubricant 101 (PN 92-13872A1) 2-4-C wTeflon (92-825407A12) Anti-Corrosion Grease (92-19007A24) 2Install components as shown