Here is a online manual for a merc 25 motor, but you will need to make sure it covers your serial #.
Boatinfo - Mercury Service Manual for 20jet-20-25hp
You will find the info for torque specs of the case and rod bolts in it and on the following pages. Be sure that the manual covers your motor before doing any work. Otherwise we need a SR# of your motor to get you needed info. JMO
Oldmasn570