1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 307Get this manual
Removal of Gearcase155 1"'" To prevent accidental starting of the engine, disconnect the charge coil connectors2Remove the oil level and the filldrain plugs (oil level plug first) to drain lubricant from the gearcaseYou will find magnet attached to the lower plugI nspect this magnet for the presence of metal chipsIf you do find chips on the magnet, they must be steel and must have come from one of the gears, bearings, or shafts within the gearcase, so make note for future reference while inspecting the internal componetsAlso inspect the lubricant for water, which will give it white milky appearance or overheating which will give the lubricant black color and burned odorReinstall the plugs temporarily after draining the gearcase3Remove the propeller and mounting hardwareI nspect the propeller for spun hub4Shift the gearcase into the Reverse position(I may be necessary to rotate the propeller shaft Remove the shift rod retaining screw