Yamaha Outboard Water Pumps & Impellers 2 Stroke Shop Yamaha Outboard Water Pumps & Impellers-2 Stroke at Wholesale Marine. Our Yamaha Water Pumps & Impellers are at the lowest prices and same day shipping! Sierra 18-3442 G Water Pump Repair Kit Sierra replacement water pump repair kit for Yamaha Outboards. Kit Contains: (1) 18-3519 Water Pump Housing Insert Cup (1) 18-3071 Impeller (1