Four winns 278 VISTA Owner's Manual page 145

NOTICE
During cold conditions, an alternate or supple-
mental heating system should be used.
Clean the sea water strainer often. Also, clean the
return air filter screens, located behind the louvered
doors and grills, at least once a month.
To winterize, refer to the manufacturer's literature
included in the owner's packet.
Interior Equipment - Section L Owner's Manual Page