Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 16Get this manual
4Inspect gear lubricant for metal particles (lubricant will have "metal flake" appearance)Presence of small amount of fine metal particles (resembling powder) on the fill screw bar magnet indicates normal gear wearAn excessive amount of metal filings or larger particles (chips) may indicate abnormal wear and requires gear housing disassembly and component inspection5Note color of gear lubricantWhite or cream color indicates presence of water in lubricantGear lubricant which has been drained from gear case recently in operation will have yellowish color due to lubricant agitationaerationThis is normal and should not be confused with the presence of water6Presence of water in gear lubricant indicates the need for disassembly and inspection of oil seals, seal surfaces, o-rings, water pump gaskets as well as gear housing components for damage Propeller Replacement
Removal
When removing or installing propeller, verify remote control is in NEUTRAL position and that key switch is "OFF Place block of wood between the anti-ventilation plate and propeller to prevent accidental engine starting and to protect hands from propeller blades while removing propeller nut