Mercury - Quicksilver Fuel Pump Cooler Kit Cooling & Fuel System Components Durable Marine-Grade Construction 8M0125846. Overview. Anyone who's run a big-block or small-block MerCruiser on a hot summer afternoon knows how good it feels when the engine stays steady, cool, and predictable. You can hear it in the tone of the exhaust and feel it in the smooth pull as you throttle up. That confidence doesn't happen by accident - it comes from parts that keep fuel temperatures under control even when