Mercury Optimax DFI 2-Stroke Marine Oil Mercury Optimax DFI 2-Stroke Outboard Oil provides the best protection in all 2-stroke applications. This oil has been formulated to provide industry-leading protection against wear and corrosion. Use of this oil minimizes carbon build-up that can affect your outboards top speed and acceleration. Additionally, Mercury OptimaxDFI oil helps maintain peak engine performance and reduces smoke. Mercury OptimaxDFI 2-stroke oil maximizes the performance of Mercur