{"product_id":"water-pump-impeller-fits-mercury-mariner-8-20-hp-four-stroke-replaces-47-803748","title":"Water Pump Impeller – Fits Mercury\/Mariner 8-20 HP Four-Stroke (Replaces 47-803748)","description":"\u003csection\u003e\n\n\u003c!-- 🔧 Table Styles (include only once per page) --\u003e\n\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eWater Pump Impeller – Fits Mercury\/Mariner 8-20 HP Four-Stroke Outboards (Replaces 47-803748)\u003c\/strong\u003e is a crucial cooling system component designed for Mercury and Mariner 8, 9.9, 10, 15, and 20 HP four-stroke outboard motors manufactured between 2005 and 2023. It ensures proper water circulation to prevent engine overheating.\u003c\/p\u003e\n\u003cp\u003eThis part is a direct interchange for Mercury part numbers 47-803748, 47-8M0214944, 47-8M0135803, 47-803748002; Sierra 18-8921; and CEF Marine 500383.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered as a direct replacement for original equipment.\u003c\/li\u003e\n\u003cli\u003eConstructed from durable neoprene rubber for reliable performance.\u003c\/li\u003e\n\u003cli\u003eIncludes one impeller for a complete replacement.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n        \u003cth\u003eSuperseded By\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e47-803748\u003c\/td\u003e\n        \u003ctd\u003e47-8M0214944\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e47-8M0135803\u003c\/td\u003e\n        \u003ctd\u003e47-8M0214944\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e47-803748002\u003c\/td\u003e\n        \u003ctd\u003e47-8M0214944\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-8921\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCEF Marine\u003c\/td\u003e\n        \u003ctd\u003e500383\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n\u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cp\u003eFor Mercury and Mariner models, it is critical to verify your engine's serial number falls within the specified ranges to ensure correct fitment.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eStroke\u003c\/th\u003e\n        \u003cth\u003eYears\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e8 HP (209cc)\u003c\/td\u003e\n        \u003ctd\u003e8\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0P325500 \u0026amp; Up, 0R042475 \u0026amp; Up\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e9.9 HP (209cc)\u003c\/td\u003e\n        \u003ctd\u003e9.9\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0P325500 \u0026amp; Up, 0R042475 \u0026amp; Up, 0N059858 \u0026amp; Up\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e10 HP (2CYL)\u003c\/td\u003e\n        \u003ctd\u003e10\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0R575531-0R833819\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e15 HP (2CYL)\u003c\/td\u003e\n        \u003ctd\u003e15\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0R235949-0R833819, 0N001590 \u0026amp; Up\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e15 HP Sea Pro\u003c\/td\u003e\n        \u003ctd\u003e15\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0R051685-0R123564, 0R123565 \u0026amp; Up\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e18 HP (2CYL)\u003c\/td\u003e\n        \u003ctd\u003e18\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0N001590-0N055284, 0N055285 \u0026amp; Up\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e20 HP (2CYL)\u003c\/td\u003e\n        \u003ctd\u003e20\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2005–2023\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eSerial #: 0R235168-0R833819\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMariner\u003c\/td\u003e\n        \u003ctd\u003e20 HP\u003c\/td\u003e\n        \u003ctd\u003e20\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2008\u003c\/td\u003e\n        \u003ctd\u003e47-803748\/47-8M0214944\u003c\/td\u003e\n        \u003ctd\u003eModels: 7F20201ZK, 7F20211ZK, 7F20302ZK, 7F20311ZK, 7F20312ZK, 7F20411ZK, 7F20412ZK\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eWater Pump Impeller\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement for original equipment\u003c\/dd\u003e\n  \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eNeoprene rubber\u003c\/dd\u003e\n  \u003cdt\u003eHousing Color\u003c\/dt\u003e\n\u003cdd\u003eBlack\u003c\/dd\u003e\n  \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e41.2 mm diameter × 23.8 mm height (1.62 in × 0.94 in)\u003c\/dd\u003e\n  \u003cdt\u003eHub Shaft Diameter\u003c\/dt\u003e\n\u003cdd\u003e14.0 mm (0.55 in)\u003c\/dd\u003e\n  \u003cdt\u003eNumber of Blades\u003c\/dt\u003e\n\u003cdd\u003e6\u003c\/dd\u003e\n  \u003cdt\u003eInternal Shaft Insert Diameter\u003c\/dt\u003e\n\u003cdd\u003e16.03 mm\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Water Pump Impeller (47-803748\/47-8M0214944)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the engine's battery and remove the lower unit (gearcase).\u003c\/li\u003e\n  \u003cli\u003eUnbolt and carefully remove the water pump housing cover.\u003c\/li\u003e\n  \u003cli\u003eObserve the rotational direction of the old impeller's blades before removal.\u003c\/li\u003e\n  \u003cli\u003eRemove the old impeller, key, gaskets, and wear plate.\u003c\/li\u003e\n  \u003cli\u003eThoroughly clean the inside of the pump housing and all mating surfaces.\u003c\/li\u003e\n  \u003cli\u003eLightly lubricate the new impeller and the inside of the pump housing with marine-grade silicone grease.\u003c\/li\u003e\n  \u003cli\u003eInstall the new wear plate, gasket, and drive key.\u003c\/li\u003e\n  \u003cli\u003eSlide the new impeller onto the driveshaft while turning the shaft clockwise to correctly seat the blades.\u003c\/li\u003e\n  \u003cli\u003eReinstall the water pump housing with a new gasket and tighten bolts to the manufacturer's specified torque.\u003c\/li\u003e\n  \u003cli\u003eReattach the lower unit and test the engine's cooling system at the ramp, ensuring a steady tell-tale stream.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if this impeller is the right one for my motor?\u003c\/summary\u003e\n  \u003cp\u003eThe best way to ensure compatibility is to check your engine's model, year, and serial number against the detailed list in our Engine \u0026amp; Model Compatibility table. Even if your HP and year match, serial number ranges are critical for confirming the fit.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the common signs of a failing water pump impeller?\u003c\/summary\u003e\n  \u003cp\u003eCommon symptoms include the engine overheating alarm sounding, a weak or non-existent water stream from the \"tell-tale\" outlet port, and in some cases, a steamy exhaust. Failure to replace a worn impeller can lead to severe engine damage.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should I replace my outboard's impeller?\u003c\/summary\u003e\n  \u003cp\u003eAs a general maintenance rule, it is recommended to replace the water pump impeller every 1 to 2 years or every 100-200 hours of operation, whichever comes first. This interval can be shorter if you frequently operate in sandy, silty, or saltwater conditions.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this aftermarket impeller as good as the original Mercury part?\u003c\/summary\u003e\n  \u003cp\u003eOur aftermarket impellers are manufactured to meet or exceed OEM specifications using high-quality neoprene rubber for durability and performance. While not an OEM part, it offers a reliable and cost-effective alternative without compromising on quality.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs any lubricant required during installation?\u003c\/summary\u003e\n  \u003cp\u003eYes, applying a light coat of marine-grade silicone grease or a soap-and-water mixture to the impeller blades and inside the pump housing will ease installation and prevent damage to the impeller during the first dry start.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the difference between OEM and aftermarket parts?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. All our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow fast is shipping and what does it cost?\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free to most regions; expedited options will appear at checkout if they are available for your location.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the warranty and return policy?\u003c\/summary\u003e\n  \u003cp\u003eThis part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for parts that are unused and in their original condition. See our full policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images and specifications against your original part before purchase. If anything differs—even if your model appears on the compatibility list—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement component, not an Original Equipment Manufacturer (OEM) part.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is highly recommended for safety, proper function, and to prevent engine damage.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Enjoy free standard delivery to most regions worldwide, typically within 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — We offer fair pricing by eliminating intermediaries, without ever compromising on materials or quality control.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50717908009275,"sku":"17IT004R","price":17.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/17IT004R.png?v=1762938139","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-fits-mercury-mariner-8-20-hp-four-stroke-replaces-47-803748","provider":"SeaSierra","version":"1.0","type":"link"}