Mercury - Cooling System Strainer V6 & V8 FourStroke / Racing Series Marine Polymer 8M0142515. Overview. There is a certain comfort that comes from knowing your engine is protected, even when the water you are running through is less than perfect. Anyone who spends time offshore or navigating shallow, debris-prone channels knows how quickly small things can turn into big problems. That is why a dependable cooling system strainer matters more than most people realize. With the Mercury Marine part