2001 Mercury Mariner 50-60HP Factory Service Manual, Page 104Get this manual
CHARGINGSTARTING SYSTEM
Battery
Recommended Battery
A 12 volt battery with minimum rating of 465 marine cranking amps (MCA) or 350 cold cranking amps (CCA)For operation below 32 (0 C) rating of 1000 Marine Cranking Amps (MCA) or 775 Cold Cranking Amps (CCA) is recommended
Operating Engine Without Battery
If desired (or in an emergency), engines equipped with an electric start and alternator can be started and operated without battery (either disconnected or removed) if "WARNING", below, is followed
WARNING