{"product_id":"sierra-18-3074-yamaha-mercury-mariner-impeller","title":"Sierra 3074 Yamaha\/Mercury\/Mariner Impeller","description":"\u003cp\u003eThe \u003cstrong\u003eSierra 3074 (18-3074) Impeller\u003c\/strong\u003e is a six-blade replacement water pump impeller for compatible Yamaha, Mercury, and Mariner 9.9–15 HP outboards. Installed inside the lower-unit water pump, it draws cooling water through the gearcase and circulates it through the engine to maintain proper operating temperature.\u003c\/p\u003e\u003ch2\u003eParts Desk Insight — Best Use\u003c\/h2\u003e\u003cp\u003eNote that \u003cstrong\u003e47-3074 can look like a Mercury OEM-format number\u003c\/strong\u003e but is the distributor SKU for Sierra 18-3074. This impeller spans two engine brands (Yamaha and Mercury\/Mariner) with different OEM cross-references — confirm the original impeller number from the engine parts diagram before removing the lower unit. For Yamaha, match to the 682-series number; for Mercury\/Mariner, match to 47-84027M, 47-84027T, or 47-96619M.\u003c\/p\u003e\u003cp\u003eReplace every 2–3 seasons or 200 hours regardless of visible wear. Impeller vanes harden and lose flexibility before showing obvious damage, reducing cooling flow without warning.\u003c\/p\u003e\u003cp\u003eThis impeller is included in Sierra water pump kits 18-3148 and 18-3411 for a complete pump service.\u003c\/p\u003e\u003ch2\u003eKey Specifications\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSierra part number: 18-3074\u003c\/li\u003e\n\u003cli\u003eSix flexible impeller blades\u003c\/li\u003e\n\u003cli\u003eFits compatible Yamaha and Mercury\/Mariner 9.9–15 HP outboards\u003c\/li\u003e\n\u003cli\u003eIncluded in Sierra water pump kits 18-3148 and 18-3411\u003c\/li\u003e\n\u003cli\u003eImpeller only — housing, wear plate, key, and gaskets not included\u003c\/li\u003e\n\u003cli\u003eUPC: 030999315267\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eEngine Compatibility\u003c\/h2\u003e\u003cp\u003eDocumented Yamaha applications (682-series water pump impeller):\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eYamaha 9.9D two-stroke: approx. 1984–1995\u003c\/li\u003e\n\u003cli\u003eYamaha 15D two-stroke: approx. 1984–1995\u003c\/li\u003e\n\u003cli\u003eYamaha F9.9A four-stroke: approx. 1985–2004\u003c\/li\u003e\n\u003cli\u003eYamaha F9.9B four-stroke: approx. 1985–1996\u003c\/li\u003e\n\u003cli\u003eYamaha FT9.9 four-stroke: approx. 1985–1990\u003c\/li\u003e\n\u003cli\u003eYamaha T9.9 four-stroke: approx. 1985–2003\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eAlso cross-referenced to select Mercury and Mariner 9.9–15 HP applications using OEM numbers 47-84027M, 47-84027T, or 47-96619M.\u003c\/p\u003e\u003cp\u003eAlways confirm by complete engine model number, production year, gearcase configuration, and OEM parts diagram. Do not order by horsepower alone.\u003c\/p\u003e\u003ch2\u003eAlternate Part Numbers\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eSierra: 18-3074 \/ 118-3074\u003c\/li\u003e\n\u003cli\u003eYamaha: 682-44352-00-00, 682-44352-01-00, 682-44352-03-00, 682-44352-40-00\u003c\/li\u003e\n\u003cli\u003eMercury\/Mariner: 47-84027M, 47-84027T, 47-96619M\u003c\/li\u003e\n\u003cli\u003eQuicksilver: 8M6013999\u003c\/li\u003e\n\u003cli\u003eMallory Marine: 9-45605\u003c\/li\u003e\n\u003cli\u003eGLM Marine: 89880\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\u003cp\u003eLower-unit removal is required to access the water pump assembly. During service: inspect the housing, wear plate, cup, key, and seals; remove any broken impeller fragments from cooling passages; lubricate the new impeller with clean soapy water or approved assembly lubricant; rotate the driveshaft in its normal operating direction while seating the housing over the blades. Confirm strong cooling-water telltale flow before operating under load. Never operate the outboard without an adequate cooling-water supply.\u003c\/p\u003e\u003ch2\u003eCompatible Water Pump Kits\u003c\/h2\u003e\u003cul\u003e\u003cli\u003e\u003ca href=\"\/products\/sierra-marine-water-pump-kit-18-3205-yamaha-9-9-15hp-2-stroke-cooling-system-rebuild\"\u003eSierra Marine Water Pump Kit 18-3205 – Yamaha 9.9–15HP 2-Stroke\u003c\/a\u003e\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eRelated Yamaha Impellers\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/products\/sierra-18-3042-yamaha-impeller\"\u003eSierra 3042 (18-3042) Yamaha Impeller\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/sierra-impeller-18-3086-ap-007-yamaha-outboard-water-pump-replacement\"\u003eSierra Impeller 18-3086 – Yamaha Outboard Water Pump Replacement\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eRelated J\/E Impellers\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/products\/sierra-18-3050-johnson-evinrude-impeller\"\u003eSierra 3050 (18-3050) Johnson\/Evinrude Impeller\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/sierra-18-3051-johnson-evinrude-impeller\"\u003eSierra 3051 (18-3051) Johnson\/Evinrude Impeller\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/sierra-18-3083-johnson-evinrude-impeller\"\u003eSierra 3083 (18-3083) Johnson\/Evinrude Impeller\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cem\u003eAlways confirm fitment against your engine service manual and full model\/year before ordering.\u003c\/em\u003e\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":51156142587940,"sku":"47-3074","price":53.29,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/0b5a116c-c870-4a2b-a336-402853bdc9c8.png?v=1785123956","url":"https:\/\/marisolmarine.com\/products\/sierra-18-3074-yamaha-mercury-mariner-impeller","provider":"Marisol Marine Company","version":"1.0","type":"link"}