Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 455Get this manual
LEFT 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" screw55Remove grease tube (or hose) from "Fill" hole and quickly install "Fill" screw into "Fill" hole
Installing Gear Housing to Driveshaft Housing
WARNING
Disconnect high tension leads from spark plugs and remove spark plugs from engine before installing gear housing onto driveshaft housing1Tilt engine to full up position and engage the tilt lock lever2Apply light coat of Quicksilver 2-4-C wTeflon Marine Lubricant onto driveshaft splines