In our 2004 Sugar Sand Mirage 1800 "fun and fish" with the Merc Jet 240 EFI, Im running Amsoil HP Marine!
In our 1997 Four Winns Vista 278 (twin 4.3 TBI engines), I am running Rotella T5 10w30. The Kohler 4kw generator gets Mobil Delvac 15w40. Amsoil Marine Gear Lube in the twin Volvo Penta SX outdrives.