Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 244Get this manual
SHIFT SHAFT ASSEMBLYCOMPONENT DISASSEMBLY AND INSPECTION
3Remove
Inspect the shift shaft splines and oil seal surface for corrosion andor excessive wearReplace the shift shaft if either if these conditions are found
a Shift Shaft Bushing
a Oil Seal Surface Spline
Q-rings (2)
Coupler Shi ft Sha ft
Clean all components with suitable solvent and dry thoroughly with compressed air