Quicksilver Premium PLUS DFI TC-W3 2-stroke oil Original Quicksilver Premium PLUS DFI oil. Quicksilver DFI OptiMax/outboard DFI oil for Mercury or Mariner OptiMax engines and 2-stroke DFI outboard engines is recommended. It must not be used in engines for which TC-W3 oil is specified. As Mercury and Mariner OptiMax engines and DFI outboard engines have increasingly higher operating temperatures and lower lubrication rates, higher quality lubricants are required. By combining synthetic additives with a modified base blend, Quicksilver OptiMax/DFI outboard engine oil is able to minimise carbon deposits while providing increased lubrication and resistance to scoring, maximising engine performance, fuel economy and reducing the amount of smoke. Quicksilver OptiMax/DFI outboard engine oil meets the lubrication requirements during the warranty period for all Mercury and Mariner OptiMax and DFI engines. DFI oil minimises carbon deposits while providing increased lubrication and resistance to fouling, maximising engine performance, fuel economy and reducing smoke. Quicksilver part number 92-858037QB1