Mercury - Quicksilver Solenoid Outboard Electrical System Marine-Grade Construction 8M0185144. Overview. There's a kind of quiet trust that builds between you and your engine after enough days on the water. You start to feel which parts are solid, which ones you never have to second-guess. This Mercury Marine part falls into that category - the kind you lean on without even thinking about it. When you turn the key at dawn, or ease back toward the dock after sunset, this solenoid delivers the cal