Ive got the same 2002 200hp Opti motor, so would like to be sure I understand, but between this post and the one of a day or so ago, Im not sure I do. Sounds like you saying that the Optimax “DFI” (Mercury) oil, which Ive been told is the same oil as the QuickSilver “synthetic blend”, contains a detergent. Unfortunately, DFI oil has been hard to get around here, so Ive had to run the Premium Plus more often than not. So the Premium Plus has no (or much less) detergent???thanx