Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 217Get this manual
General Service Recommendations There may be more than one way to "disassemble" or particular part(s) It is recommended that the entire procedure be read prior to repair
Keep record of all shim amounts and location during disassembly to aid in reassemblyBe sure to follow shimming instructions during reassembly as gears must be installed to correct depth and have the correct amount of backlash to avoid noisy operation and premature gear failure
IMPORTANT: Read the following before attempting cny repairs