Mercury - Quicksilver 10W-30 4-Stroke Marine Engine Oil, 1 Quart Marine Engine Oil Standard Finish 8M0078616. Overview. Any boater who spends real time on the water knows how much comfort comes from turning the key and hearing an engine settle into a smooth, confident idle. It is a small moment, but it sets the tone for the whole day - whether you are easing toward the channel marker or heading out with a cooler full of bait and big hopes. Quicksilver 10W-30 4-Stroke Marine Engine Oil, part numb