Quicksilver 92-8M0053664 25W-50 4-Stroke Synthetic Marine Oil The Quicksilver 25W-50 Synthetic Blend Oil is recommended for engines used in high performance applications. This oil provides maximum lubrication for your marine engine while also protecting against varnish buildup and sludge formation. For racing vessels, this oil maintains viscosity while operating the engine at maximum output and high temperatures. For tow sports and fishing, this oil maintains viscosity while alternating between