Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 277Get this manual
9 Form tool using 118 in (3 mm) wire as shown in the following figure and remove the forward gear bearing adaptor
10Shift gear case into forward gearNOTE: The thrust race has tight fit in the gear housing boreUse the Forward Gear Installation Tool (91-815850) to remove the thrust race and the forward gear togetherIf this attempt fails, form small hook on the end of stiff piece of wire and while applying heat to the outside of gear casepull the thrust race up and out of the gear housing11 Remove the -ring from inside the gear housing12Remove the forward gear, thrust race, and the thrust bearing (between the gear and the race)13Remove the forward gear shim