Guys, We just picked up a Cherry 1996 Sea Ray 215 Express Cruiser with 320 hours. It was pretty much spotless, which sold my wife. It has been in one family its entire life and has been well maintained. My question being a member this forum for so long is "Which oil do i Need?" He has used Pennzoil Platinum 5w-40 for a while. I use the Ultra Platinum 5w-30 in my 3.6L Wrangler JKU. And love it. Should I stick with the 5w-40 or go to the Diesel 15w-40 T6? Does the 96 Mercruiser 5.7L need the high Zinc? I want to give the boat the best and keep it for a long time and keep that smile on my wife's face!