I just purchased a Exmark 66" with a 31hp Vanguard engine(Love it by the way). My Dealer gave me one 48oz jug of SAE 30 . The service book is not very clear, but I didnt think a straight 30 weight was meant to be run with a filtered engine. I also dont think 48oz is enough oil. The book seemed to say around 80oz. Thanks for the help!!!