Mercury - Heavy Duty Sea Water Pump Impeller Repair Kit MerCruiser 4.5L & 6.2L Composite & Elastomer 8M0137220. Overview. There's a certain calm that settles over you when you know your cooling system is ready for whatever the day brings. It's the kind of confidence that comes from installing a part built exactly for the engine you trust. With the Mercury 8M0137220 Heavy Duty Sea Water Pump Impeller Repair Kit, you'll feel that same sense of security-whether you're easing out of the no-wake zone