{"product_id":"sierra-18-3013-upper-water-pump-seal-replaces-mercury-mariner-26-821309-fits-25-30-40-45-50-hp-4-stroke-outboards-s-n-og760300-up","title":"Sierra 18-3013 Upper Water Pump Seal, Replaces 26-821309, Fits 25\/30\/40\/45\/50 HP 4-Stroke Outboards","description":"\u003cp\u003eThe Sierra 18-3013 is an upper water pump seal used to restore a tight, factory-spec seal in the water pump housing of covered outboard engines. As the pump wears, this upper seal is one of the first components to lose its sealing ability, allowing cooling water to bypass the pump and reducing water flow to the engine. Replacing it as part of a water pump rebuild helps maintain proper cooling water pressure and delivery.\u003c\/p\u003e\u003cp\u003ePart 18-3013 is a direct equivalent to OEM number 26-821309 and is designed specifically for 4-stroke outboards rated 25, 30, 40, 45, and 50 HP with serial number OG760300 and up. Because fitment is tied to that serial number range, confirm your engine's serial number before ordering to make sure this is the correct seal for your unit. At 0.02 pounds, it is a small, lightweight component intended to be installed alongside the other water pump wear parts (impeller, gaskets, and housing) during a routine pump rebuild.\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 18-3013\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Upper Water Pump Seal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 26-821309\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment:\u003c\/strong\u003e 4-Stroke Outboards, 25\/30\/40\/45\/50 HP, serial number OG760300 and up\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.02 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282112851\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e4-Stroke Outboards, 25\/30\/40\/45\/50 HP, serial number OG760300 and up\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e26-821309\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part number does the Sierra 18-3013 seal replace?\u003c\/strong\u003e It replaces OEM number 26-821309. The Sierra 18-3013 upper water pump seal is a direct equivalent, so you can order it using either number.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhich outboard engines fit the 18-3013 upper water pump seal?\u003c\/strong\u003e This seal is designed for 4-stroke outboards rated 25, 30, 40, 45, and 50 HP with serial number OG760300 and up.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the engine serial number matter when ordering this seal?\u003c\/strong\u003e Yes. The Sierra 18-3013 is fitted specifically to 4-stroke outboards with serial number OG760300 and up, so confirming your engine's serial number before ordering ensures correct fitment.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-3013 seal weigh?\u003c\/strong\u003e It weighs 0.02 pounds, making it a lightweight component of a water pump rebuild kit or standalone repair.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-3013 a genuine Sierra part or aftermarket?\u003c\/strong\u003e The 18-3013 is a Sierra-branded upper water pump seal, sold under Sierra's own part number and manufactured to their specification.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat does the upper water pump seal actually do?\u003c\/strong\u003e In the water pump assembly, this seal keeps cooling water contained within the pump housing so it is delivered to the engine rather than leaking past worn components; the Sierra 18-3013 replaces this seal when it wears out.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the 18-3013 fit outboards outside the 25-50 HP range?\u003c\/strong\u003e Fitment for the Sierra 18-3013 is specified for 25, 30, 40, 45, and 50 HP 4-stroke outboards with serial number OG760300 and up; it is not listed for other horsepower ratings.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when you order part 18-3013?\u003c\/strong\u003e Ordering Sierra part 18-3013 gets you a single upper water pump seal.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs there more than one cross-reference number for this seal?\u003c\/strong\u003e No, the Sierra 18-3013 upper water pump seal has one listed OEM cross-reference: 26-821309.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the UPC for the Sierra 18-3013 seal?\u003c\/strong\u003e The UPC for the Sierra 18-3013 upper water pump seal is 808282112851.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988136767707,"sku":"SIE-18-3013","price":1.81,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3013_lg__68533.1558125330.500.750.jpg?v=1785329145","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3013-upper-water-pump-seal-replaces-mercury-mariner-26-821309-fits-25-30-40-45-50-hp-4-stroke-outboards-s-n-og760300-up","provider":"Good Vibes Marina","version":"1.0","type":"link"}