{"product_id":"sierra-18-3006-water-pump-impeller-for-johnson-evinrude-outboard-replaces-omc-378891-775521-6-fin-neoprene","title":"Sierra 18-3006 Neoprene Water Pump Impeller with 6 Fins - Johnson\/Evinrude 40 HP 1971-73","description":"\u003cp\u003eThe Sierra 18-3006 is a neoprene water pump impeller built for Johnson\/Evinrude outboard motors, specifically the 40 HP models from 1971-73. This impeller is the core wear component of the outboard's water pump, drawing raw water from the intake and pushing it through the cooling system to keep the powerhead running at a safe temperature. Made from neoprene, it is molded with 6 fins that flex and reseat against the pump housing as the drive shaft turns, creating the pumping action that circulates cooling water. Neoprene is chosen for this application because it resists the heat, fuel exposure, and constant flexing that a water pump impeller experiences in service, while holding its shape for a consistent seal against the pump housing.\u003c\/p\u003e\u003cp\u003eSierra engineers and manufactures this impeller to meet or exceed original equipment quality, so it installs and performs as a direct replacement in the applications listed. Replacing a worn or cracked impeller at recommended service intervals helps prevent overheating, which can otherwise lead to costly powerhead damage. This impeller is sold individually and is intended to be installed as part of a routine water pump service or 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 18-3006\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Water Pump Impeller\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Neoprene\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNumber of Fins:\u003c\/strong\u003e 6\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.06 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross-Reference:\u003c\/strong\u003e OMC 378891, 775521\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eJohnson\/Evinrude 40 HP, 1971-73\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eOMC 378891\u003c\/li\u003e\n\u003cli\u003eOMC 775521\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-3006 impeller fit?\u003c\/strong\u003e The 18-3006 is built for Johnson\/Evinrude outboard motors in the 40 HP application from 1971-73.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the 18-3006 impeller made of?\u003c\/strong\u003e It is molded from neoprene, a material chosen for its resistance to heat and flexing inside a marine water pump.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many fins does this impeller have?\u003c\/strong\u003e The Sierra 18-3006 has 6 fins that create the pumping action drawing raw water through the outboard's cooling system.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-3006 cross-reference to an OEM part number?\u003c\/strong\u003e Yes, it is equivalent to OMC 378891 and OMC 775521.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-3006 an OEM part or an aftermarket replacement?\u003c\/strong\u003e It is a Sierra-manufactured aftermarket impeller built to meet or exceed original equipment quality, not an OMC-branded part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-3006 impeller weigh?\u003c\/strong\u003e It weighs 0.06 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the Sierra 18-3006 impeller?\u003c\/strong\u003e It is white, the natural color of the neoprene compound it is molded from.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan the 18-3006 be used on any Johnson\/Evinrude outboard?\u003c\/strong\u003e No, fitment is specific to the 40 HP 1971-73 application; buyers should confirm their engine model and year before ordering since Sierra lists different impeller part numbers for other years and horsepower ranges.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow often should a water pump impeller like the 18-3006 be replaced?\u003c\/strong\u003e A neoprene impeller such as the 18-3006 is a wear item that should be replaced whenever it shows cracking, worn fins, or reduced water flow, or as part of routine water pump service.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat happens if I run my outboard with a worn 18-3006 impeller?\u003c\/strong\u003e A worn impeller reduces raw water flow through the cooling system, which can cause the outboard to overheat and potentially damage the powerhead.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-3006 come with the water pump housing or gaskets?\u003c\/strong\u003e No, the 18-3006 is the neoprene impeller only.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988136603867,"sku":"SIE-18-3006","price":22.55,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3006_lg__62129.1558125018.500.750.jpg?v=1785188759","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3006-water-pump-impeller-for-johnson-evinrude-outboard-replaces-omc-378891-775521-6-fin-neoprene","provider":"Good Vibes Marina","version":"1.0","type":"link"}