Mercury Mariner 4, 5 102CC Sail 1990 Outboard Service Shop Manual, Page 113Get this manual
Filling Gear Housing With Lubricant IMPORTANT: DO NOT use automotive lubricant in gear housingUse only Quicksilver Gear Lube1Remove any ld gasket material from "O IL" andOIL LEVEL" plugs and from around plug openings of gear housing 2Insta ll new gaskets on "OIL" and "O IL LEVEL" plugs
5Install "O IL LEVEL" (vent) plug (a) SRemove lubricant tube and install "O IL" (fill) plug (b)
IMPORTANT: Never add lubricant to gear housing without first removingOIL LEVEL" (vent) plug, as trapped afr will prevent housing trom being filledFill gear housing only when outboard Is in operating position