Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 398Get this manual
RIGHT HAND NON-RATCHETING
Gear Lubricant Filling Instructions
1Remove any gasket material from "Fill" and "Vent" screws and gear housing2Install new gaskets on Fill and Vent screwsIMPORTANT: Never apply lubricant to gear housing without first removing Vent screw, or gear housing cannot be filled because of trapped airFill gear housing ONLY when housing is in vertical position3Slowly fill housing thru Fill hole with Quicksilver Super Duty Lower Unit Lubricant until lubricant flows out of "Vent" hole and no air bubbles are visible4Install Vent screw into Vent holeIMPORTANT: DO NOT lose more than one fluid ounce (30cc) of gear lubricant while reinstalling Fill screw5Remove grease tube (or hose) from Fill hole and quickly install Fill screw into Fill hole
Installing Gear Housing to Driveshaft Housing
WARNING