Mercury - Rotor Ignition System Component Marine-Grade Coated Brass 8M6001253. Overview. When you turn the key on a MerCruiser V8, you expect that familiar, confident rumble to light off without hesitation. That moment - whether you're easing out for an early morning cruise or getting ready to push toward open water - depends on a clean, reliable spark. The Quicksilver 8M6001253 Rotor, designed for General Motors V8 engines equipped with Delco High Energy Ignition (HEI) systems, helps keep that