Mercury - Quicksilver 10W-30 4-Stroke Marine Engine Oil, 1 Gallon Marine Engine Oil Standard Finish 8M0078617. Overview. There's a certain comfort that comes from knowing your engine is protected by oil you trust. When you turn the key and hear that steady, easy rumble, you feel the whole day settling into place. Quicksilver 10W-30 4-Stroke Marine Engine Oil, part number 8M0078617, is the kind of oil seasoned boaters rely on because it keeps their engines calm, cool, and dependable. Whether you