Quicksilver Premium Plus 2-Stroke Synthetic Marine Oil The synthetic blend of Premium Plus Quicksilver oil features an advanced formula specially designed for all 2-stroke outboard engine applications. More specifically, the oil was created to meet the challenging demands of high horsepower engines. Quicksilver oil is blended with high-quality ash-free dispersants. The advanced formula helps to maintain peak engine performance in even the most severe conditions including extended full throttle,