Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 185Get this manual
8Remoye bolt (or nut) and washer from front of gear housing9Disconnect speedometer hose (if connected)10Loosen the side mounting locknuts(DO NOT attempt to remove one nut before all nuts are loosened sufficiently, or drive shaft housing could be damaged 11Pull gear housing away from drive shaft housing as far as the loosened nuts (in Step 10) will allow, then remove loosened nuts(00 NOT allow gear housing to fall, as it now is free 12Pull gear housing from drive shaft housing 3Inspect gear lubricant for metal particlesPresence of small amount of fine metal particles (resembling powder) indicates normal wearPresence of larger particles (or large quantity of fine particles) indicates need for gear housing disassembly, and component inspection4Note the color of gear lubricantWhite or cream color indicates presence of water in lubri can tCheck drain pan for water separation from lubricantPresence of water in gear lubricant indicates the need for disassembly, and inspection of oil seals, seal surfaces, "0" rings and gear housing componentsGear lubricant which has been drained from gearcases recently operated may have yellowish tint appearanceThis is due to agitation aeration 00 NOT mistake this for water contamination