1999 "EE" 90, 115 FFI, 150, 175 V4, V6 FFI Outboards Service Manual, P/N 787024, Page 231Get this manual
Gearcase ServicingCounter-Rotation Removal Remove the gearcase as described on Page 11-11Disassembly,
1Remove the propeller and mounting hardwareInspect the propeller for spun hub
2Remove the oil level plugthen the drainlfill plugand drain the lube from the gearcase into containerInspect the lube and the magnets on the plugs for metal chipsThe presence of small metal chips can indicate normal wear of the gears, bearings, or shafts within the gearcaseLarge metal chips can indicate extensive internal damageMake note for future reference while inspecting internal components
Inspect the drained lubricant for water or burned odorWater in the lubricant will give it milky appearanceOverheating will give the lubricant black color and burned odor