Mercury - Fuel Pump MerCruiser V8 GM Series Marine-Grade Mechanical Pump 861677T. OverviewOut on the water, nothing feels better than an engine that responds instantly-smooth, strong, and ready to run. Whether you're pushing a big V8 through open chop or easing away from the dock with friends aboard, you want to know your fuel system is doing its job without hesitation. That's where a dependable mechanical pump really earns its place. The Mercury Marine part number 861677T Fuel Pump is built for