{"product_id":"sierra-18-3446-water-pump-kit-for-mercury-4-4-5-hp-outboards-replaces-46-70941a3","title":"Sierra 18-3446 Water Pump Kit - Replaces Mercury 46-70941A3 - Fits 4\/4.5 HP 1-Cylinder Outboards","description":"\u003cp\u003eThe Sierra 18-3446 Water Pump Kit is a complete impeller service kit built for 4 HP and 4.5 HP, 1-cylinder outboard motors that use a.456 inch I.D. Water impeller. This kit is the go-to fix when an outboard starts running hot or loses its telltale water stream, since the impeller and impeller plate are the two components that wear out and cause cooling failures over time.\u003c\/p\u003e\u003cp\u003eInside the kit you get a matched pair of parts designed to work together: the impeller (Sierra 18-3039, O.E. #47-89981) and the impeller plate (Sierra 18-3139, O.E. #46895). Replacing both at the same time, rather than the impeller alone, restores proper water pump sealing and flow, since a worn plate can cause a new impeller to fail prematurely.\u003c\/p\u003e\u003cp\u003eThe Sierra 18-3446 is built to meet or exceed the original equipment part it replaces and is a direct interchange for Mercury 46-70941A3, so it installs in place of the original Mercury water pump kit without modification. It is sized specifically for 4 HP and 4.5 HP, 1-cylinder outboards using the.456 inch I.D. Water impeller design, making it important to confirm your impeller bore diameter before ordering.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-3446\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Water Pump Kit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHorsepower Fitment:\u003c\/strong\u003e 4 HP and 4.5 HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder Configuration:\u003c\/strong\u003e 1 cylinder outboard motors\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWater Impeller Inside Diameter:\u003c\/strong\u003e 0.456 inch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKit Contents:\u003c\/strong\u003e Impeller (18-3039), Impeller Plate (18-3139)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImpeller OEM Part Number:\u003c\/strong\u003e 47-89981\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eImpeller Plate OEM Part Number:\u003c\/strong\u003e 46895\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 46-70941A3\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.4 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282111939\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e4 HP and 4.5 HP, 1-cylinder outboard motors with a.456 inch I.D. Water impeller\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e46-70941A3\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-3446 water pump kit include?\u003c\/strong\u003e The kit includes an impeller (Sierra 18-3039, O.E. #47-89981) and an impeller plate (Sierra 18-3139, O.E. #46895), the two components needed to rebuild the water pump on a compatible outboard.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat outboards does the Sierra 18-3446 fit?\u003c\/strong\u003e This kit fits 4 HP and 4.5 HP, 1-cylinder outboard motors that use a.456 inch I.D. Water impeller.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-3446 a direct replacement for Mercury 46-70941A3?\u003c\/strong\u003e Yes, the Sierra 18-3446 water pump kit is interchangeable with Mercury 46-70941A3.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow do I know if my impeller needs replacing?\u003c\/strong\u003e A weak or absent telltale water stream, an overheating outboard, or a rubber impeller with cracked or worn vanes are signs that the water pump kit, such as the Sierra 18-3446, needs replacement.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eShould I replace the impeller plate along with the impeller?\u003c\/strong\u003e Yes, the Sierra 18-3446 kit pairs the impeller with the impeller plate because a worn plate can cause a newly installed impeller to fail early, so both parts are replaced together.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the Sierra 18-3446 meet original equipment quality standards?\u003c\/strong\u003e Sierra states this water pump kit meets or exceeds the original equipment part it replaces, namely Mercury 46-70941A3.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the water impeller bore size on the Sierra 18-3446 kit?\u003c\/strong\u003e The impeller in this kit has a.456 inch inside diameter, which is specific to the 4 HP and 4.5 HP, 1-cylinder outboards it is designed for.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-3446 water pump kit weigh?\u003c\/strong\u003e The Sierra 18-3446 water pump kit weighs 0.4 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan this kit be used on multi-cylinder outboards?\u003c\/strong\u003e No, the Sierra 18-3446 is designed for 1-cylinder outboard motors in the 4 HP and 4.5 HP range with a.456 inch I.D. Water impeller, not multi-cylinder engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the OEM part number that the Sierra 18-3039 impeller replaces?\u003c\/strong\u003e The impeller included in the Sierra 18-3446 kit, part 18-3039, replaces O.E. Part number 47-89981.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the OEM part number that the impeller plate replaces?\u003c\/strong\u003e The impeller plate in the Sierra 18-3446 kit, part 18-3139, replaces O.E. Part number 46895.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988149022939,"sku":"SIE-18-3446","price":66.3,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3446_lg__52855.1558127406.500.750.jpg?v=1785188148","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3446-water-pump-kit-for-mercury-4-4-5-hp-outboards-replaces-46-70941a3","provider":"Good Vibes Marina","version":"1.0","type":"link"}