Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 53Get this manual
3 Reconnect electrical harness to alternator
NOTE: belt tensioning tool (obtain locally) may also bE used to adjust belt tensionAdjust belt tension to 80 Ib (355.8 N)
Pivot Bolt Tension Boll
c Harness
Move alternator away from flywheel to increase tensionTighten tension adjustment bolt [Torque to 1751bin (20.0 Nm)) and pivot bolt [Torque to 175 1bin (20.0 Nm)]