1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 287Get this manual
Removal of Gearcase100ill the charge coil connectors To prevent accidental starting of the engine, disconnect
2Remove the propeller and mounting hardwareInspect the propeller for spun hub3Shift the gearcase into the Reverse position (It may be necessary to rotate the propeller shaft Remove the shift rod retaining screw4Note the index mark on the gearcase to align with the index number on the adjustable trim tab so that the trim tab can be reinstalled in the same positionRemove the screw and the trim tab5Using 58" thin wall socket, remove the screw the lockwasher6Using 12" socket, remove the screw
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7Remove the four gearcase retaining screws with lock washers (two each port and starboard)8Remove the gearcase assembly from the exhaust housing, being careful not to bend the shih rodThe lower inner exhaust housing may come out with the gearcaseSecure the gearcase in suitable holding fixture9Remove the oil level and the filldrain plugs (oil level plug first) to drain lubricant from the gearcaseYou will fi nd magnet attached to the lower lugInspect th is 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 componentsAlso 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 gearcase