{"title":"Mercury 4-Stroke 25-50HP Outboard Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eThis page is for Mercury 4-Stroke 25–50HP outboard engines. Use it to find compatible parts and key service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse our main Mercury collection. Scroll to the bottom of this page to start browsing parts for this engine, and on the collection page use the “Filter \u0026amp; Sort” controls to narrow results by horsepower, year range, and part category.\u003c\/p\u003e\n  \u003cp\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;padding:10px 14px;border:1px solid #0a3d62;border-radius:6px;text-decoration:none;\"\u003eBrowse All Mercury Parts\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eHow to Identify Your 25–50HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eFind the serial number plate on the starboard (right) transom bracket or swivel bracket. The same number is often on a sticker under the engine cowl.\u003c\/li\u003e\n    \u003cli\u003eMercury uses serial numbers as the primary identifier. Suffixes may indicate shaft length (S\/L\/XL), starting method (manual\/electric), tiller vs remote, and power trim.\u003c\/li\u003e\n    \u003cli\u003eConfirm platform: 25\/30 EFI vs 40\/50 EFI. 40\/50 models may have standard or Command Thrust (CT\/BigFoot) gearcases—propeller and some gearcase parts differ.\u003c\/li\u003e\n    \u003cli\u003eVerify it’s a 4-stroke: you’ll have an engine oil fill and filter; there is no separate 2-stroke oil tank.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eEngine\/Platform Overview\u003c\/h2\u003e\n\n  \u003ch3\u003eMercury 25\/30 EFI 4‑Stroke\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:940px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eConfiguration\u003c\/td\u003e\n        \u003ctd\u003eInline‑3 EFI 4‑stroke, small mid‑range outboard\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003e25 EFI, 30 EFI (tiller or remote; manual\/electric start; various shaft lengths)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eLight weight, quiet operation, low fuel consumption, easy starting\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eMany routine service parts (plugs, anodes, water pump kits) are shared across 25\/30, but verify by serial number.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eMercury 40\/50 EFI 4‑Stroke (incl. Command Thrust\/BigFoot)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:940px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eConfiguration\u003c\/td\u003e\n        \u003ctd\u003eInline‑3 EFI 4‑stroke; standard or Command Thrust (CT\/BigFoot) gearcase options\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003e40 EFI, 50 EFI; CT\/BigFoot variants for larger propellers and improved thrust\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eStrong mid‑range torque, reliable EFI manners, good trolling control\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eCT\/BigFoot gearcases use different propellers and some gearcase components versus standard models; many service items overlap with the 60 EFI but confirm by serial.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"service-kits\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines for typical recreational use. Always follow the official Mercury service manual for your exact model and operating conditions.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;max-width:940px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eEngine oil + filter\u003c\/td\u003e\n        \u003ctd\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd\u003eWarm engine before draining; replace crush washer if applicable\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/oil-filters\"\u003eOil Filters\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd\u003eInspect for water (milky) or metal; replace drain screw gaskets\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-lower-unit-seal-kits\"\u003eMercury Lower Unit Seal Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd\u003eInspect every 100 hours; replace as needed\u003c\/td\u003e\n        \u003ctd\u003eSet gap to spec; replace if fouled or at service limit\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003eSpark Plugs\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eFuel filter \/ water-separating filter\u003c\/td\u003e\n        \u003ctd\u003eEvery 100 hours or seasonally\u003c\/td\u003e\n        \u003ctd\u003eReplace sooner if poor fuel quality or storage issues are suspected\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eWater pump impeller \/ kit\u003c\/td\u003e\n        \u003ctd\u003eEvery 200 hours or 2–3 seasons\u003c\/td\u003e\n        \u003ctd\u003eCritical for cooling; replace more frequently in sandy\/silty water\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-water-pump-repair-kits\"\u003eMercury Water Pump Repair Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAnodes (sacrificial)\u003c\/td\u003e\n        \u003ctd\u003eInspect every 50 hours; replace when 50% consumed\u003c\/td\u003e\n        \u003ctd\u003eChoose alloy for your water type (zinc, aluminum, magnesium)\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n  \u003cp style=\"font-size:12px;color:#555;\"\u003e*Follow the most conservative interval that matches your usage and environment.\u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"common-parts\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eRoutine Service Kits – \u003ca href=\"https:\/\/seasierra.com\/collections\/service-maintenance-kits\"\u003eService \u0026amp; Maintenance Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCooling System – \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-water-pump-repair-kits\"\u003eMercury Water Pump Repair Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eFuel System – \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eIgnition \/ Electrical – \u003ca href=\"https:\/\/seasierra.com\/collections\/electrical-items\"\u003eElectrical Items\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003ePropulsion – \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eGearcase Seals – \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-lower-unit-seal-kits\"\u003eMercury Lower Unit Seal Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCorrosion Protection – \u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%;max-width:940px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eWeak telltale stream or overheat alarm\u003c\/td\u003e\n        \u003ctd\u003eInspect intake screens for debris; verify telltale hose is clear; confirm impeller age\u003c\/td\u003e\n        \u003ctd\u003eWater pump repair kit, thermostat, intake screen\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eHard starting or rough idle\u003c\/td\u003e\n        \u003ctd\u003eCheck fuel quality and primer bulb; battery voltage and connections; verify kill-switch lanyard\u003c\/td\u003e\n        \u003ctd\u003eSpark plugs, fuel filter, injector service\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003ePoor acceleration or power loss\u003c\/td\u003e\n        \u003ctd\u003eInspect propeller for damage or hub slip; check for restricted fuel flow; confirm throttle travel\u003c\/td\u003e\n        \u003ctd\u003ePropeller, fuel filter, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNo charging \/ battery drains\u003c\/td\u003e\n        \u003ctd\u003eMeasure charging voltage at idle and cruise; inspect rectifier\/regulator connectors for corrosion\u003c\/td\u003e\n        \u003ctd\u003eRectifier\/regulator, battery cables\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGearcase noise or milky gear oil\u003c\/td\u003e\n        \u003ctd\u003eVerify correct oil level; look for water intrusion; check prop‑shaft seal after line\/rope strikes\u003c\/td\u003e\n        \u003ctd\u003eLower unit seal kit, drain screw gaskets, prop‑shaft seals\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"faq\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre parts interchangeable between 25\/30 and 40\/50 EFI models?\u003c\/summary\u003e\n    \u003cp\u003eSome service items cross over (plugs, anodes, certain filters), but many components differ by platform and by gearcase (standard vs Command Thrust). Always confirm by serial number before ordering.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should I replace the water pump impeller?\u003c\/summary\u003e\n    \u003cp\u003eAs a rule of thumb, every 200 hours or 2–3 seasons—sooner if operating in sandy, silty, or weedy areas, or if the telltale stream weakens.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change lower unit gear oil?\u003c\/summary\u003e\n    \u003cp\u003eChange gear oil every 100 hours or annually. If you see water (milky oil) or metal shavings, service seals and recheck after a short run.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information do I need to confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003eProvide the engine’s serial number, horsepower, 4‑stroke designation, shaft length, tiller vs remote control, and whether the gearcase is standard or Command Thrust\/BigFoot.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eReady to find the exact parts for your Mercury? Browse the main Mercury collection and narrow by horsepower, year, and model.\u003c\/p\u003e\n  \u003cp\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;padding:10px 14px;border:1px solid #0a3d62;border-radius:6px;text-decoration:none;\"\u003eShop Mercury Outboard Parts\u003c\/a\u003e\u003c\/p\u003e\n  \u003cp style=\"font-size:12px;color:#555;\"\u003eIf you’re unsure about your model, send us a photo of the nameplate and the part you need and we’ll help verify compatibility.\u003c\/p\u003e\n\u003c\/section\u003e","products":[{"product_id":"water-pump-impeller-fits-mercury-mariner-15-50-hp-replaces-47-8508910","title":"Water Pump Impeller for Mercury\/Mariner 2-Stroke 15–30 HP and Select 4-Stroke Models","description":"\u003csection\u003e\n\u003cstyle\u003e\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td { padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top; }\n  table.ss-table th { white-space:nowrap; word-break:normal; letter-spacing:normal; font-weight:600; background:#f8fafc; }\n  @media (max-width:480px){ table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; } }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis aftermarket \u003cstrong\u003ewater pump impeller\u003c\/strong\u003e is designed for specified Mercury and Mariner outboard applications. The company fitment records identify this impeller for Mercury\/Mariner 2-stroke 15–30 HP engines and the listed 4-stroke models below. It is intended as a direct replacement for the original water-pump impeller when the engine, model, stroke type, and part-number reference match.\u003c\/p\u003e\n\u003cp\u003eThe primary replacement references documented for this impeller are Mercury part numbers \u003cstrong\u003e47-85089-3\u003c\/strong\u003e, \u003cstrong\u003e47-85089-10\u003c\/strong\u003e, \u003cstrong\u003e47-85089\u003c\/strong\u003e, and \u003cstrong\u003e47-8508910\u003c\/strong\u003e. Sierra \u003cstrong\u003e18-3057\u003c\/strong\u003e and Mallory \u003cstrong\u003e9-45303\u003c\/strong\u003e are listed as aftermarket reference numbers.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eSingle aftermarket water pump impeller; not a complete repair kit.\u003c\/li\u003e\n  \u003cli\u003eDesigned for the specified Mercury and Mariner 2-stroke and 4-stroke applications.\u003c\/li\u003e\n  \u003cli\u003eHigh-volume, long-vane impeller configuration associated with the documented 47-85089-10 reference.\u003c\/li\u003e\n  \u003cli\u003eConfirm the original impeller, engine model, stroke type, and part number before ordering.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse these references for identification and cross-checking. Number listings are reference information and do not replace confirmation of the complete engine application.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand or Source\u003c\/th\u003e\n\u003cth\u003eReference Number\u003c\/th\u003e\n\u003cth\u003eRole\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e47-85089-3\u003c\/td\u003e\n\u003ctd\u003eOEM reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e47-85089-10\u003c\/td\u003e\n\u003ctd\u003eOEM reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e47-85089\u003c\/td\u003e\n\u003ctd\u003eOEM reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e47-8508910\u003c\/td\u003e\n\u003ctd\u003eOEM reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-3057\u003c\/td\u003e\n\u003ctd\u003eAftermarket reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMallory\u003c\/td\u003e\n\u003ctd\u003e9-45303\u003c\/td\u003e\n\u003ctd\u003eAftermarket reference\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\u003eThe company fitment records cover the following application groups. For the 2-stroke range, verify the exact engine model and serial-number range because the supplied company data identifies the range by horsepower only.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Mercury and Mariner Engine Compatibility\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eStroke\u003c\/th\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003cth\u003eModel or Description\u003c\/th\u003e\n\u003cth\u003eFitment Note\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e15–30 HP\u003c\/td\u003e\n\u003ctd\u003eSpecified 2-stroke outboards\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model and serial number.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e8 HP\u003c\/td\u003e\n\u003ctd\u003eBodensee; internal application listing\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e9.9 HP\u003c\/td\u003e\n\u003ctd\u003e323 cc\u003c\/td\u003e\n\u003ctd\u003eInternational or model-specific application; confirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e13.5 HP\u003c\/td\u003e\n\u003ctd\u003eInternational\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e15 HP\u003c\/td\u003e\n\u003ctd\u003eSpecified 4-stroke model\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e25 HP\u003c\/td\u003e\n\u003ctd\u003eSpecified 4-stroke model\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e30 HP\u003c\/td\u003e\n\u003ctd\u003eStandard and 3-cylinder EFI applications\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e40 HP\u003c\/td\u003e\n\u003ctd\u003eStandard, 3-cylinder carbureted, Italy, and specified 3-cylinder EFI applications\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e45 HP\u003c\/td\u003e\n\u003ctd\u003eBodensee\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e50 HP\u003c\/td\u003e\n\u003ctd\u003eStandard and Bigfoot\u003c\/td\u003e\n\u003ctd\u003eConfirm exact model.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eWater pump impeller\u003c\/dd\u003e\n  \u003cdt\u003eProduct Configuration\u003c\/dt\u003e\n\u003cdd\u003eSingle impeller\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n\u003cdd\u003eMercury \/ Mariner outboard cooling systems\u003c\/dd\u003e\n  \u003cdt\u003eVane Configuration\u003c\/dt\u003e\n\u003cdd\u003eHigh-volume, long-vane design\u003c\/dd\u003e\n  \u003cdt\u003eOutside Diameter\u003c\/dt\u003e\n\u003cdd\u003eApproximately 73.0 mm (2.875 in)\u003c\/dd\u003e\n  \u003cdt\u003eInside Diameter\u003c\/dt\u003e\n\u003cdd\u003eApproximately 16.0 mm (0.625 in)\u003c\/dd\u003e\n  \u003cdt\u003eHeight\u003c\/dt\u003e\n\u003cdd\u003eApproximately 12.6 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\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e The company record identifies this product as a single impeller, not a kit. A key, gasket, washers, O-rings, wear plate, and other water-pump service parts are not included unless separately stated in the order details.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eVerify the engine model, stroke type, serial number, and original impeller reference before beginning work.\u003c\/li\u003e\n  \u003cli\u003eDisconnect the battery and follow the outboard manufacturer’s service procedure for removing the lower unit.\u003c\/li\u003e\n  \u003cli\u003eRemove the water-pump housing and take out the old impeller.\u003c\/li\u003e\n  \u003cli\u003eInspect the housing, wear plate, keyway, gaskets, O-rings, and related components for wear or damage. Replace service parts as required.\u003c\/li\u003e\n  \u003cli\u003eClean the housing and mating surfaces before installing the replacement impeller.\u003c\/li\u003e\n  \u003cli\u003eInstall the impeller using the correct key and orient the vanes in the direction specified by the engine manufacturer.\u003c\/li\u003e\n  \u003cli\u003eReassemble the water pump and lower unit using the manufacturer’s torque specifications.\u003c\/li\u003e\n  \u003cli\u003eRun the engine according to the manufacturer’s testing procedure and confirm proper cooling-water flow before normal operation.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eMaintenance \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I confirm that this impeller fits my engine?\u003c\/summary\u003e\n  \u003cp\u003eMatch your engine brand, horsepower, stroke type, exact model, and serial number to the compatibility information. Also compare the original impeller and its manufacturer reference with the documented references, including Mercury 47-85089-3 or 47-85089-10 and Sierra 18-3057.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this a complete water-pump kit?\u003c\/summary\u003e\n  \u003cp\u003eNo. This product is a single aftermarket water pump impeller. It does not include a key, gasket, washers, O-rings, wear plate, housing, or other repair-kit components.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a worn water-pump impeller?\u003c\/summary\u003e\n  \u003cp\u003ePossible signs include weak cooling-water flow, overheating warnings, or overheating during operation. Inspect the complete cooling system because water-flow problems can have causes other than the impeller.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShould the key and gaskets be replaced at the same time?\u003c\/summary\u003e\n  \u003cp\u003eInspect the key, housing, wear plate, gaskets, and O-rings during service. Replace any worn, damaged, hardened, or distorted components with parts appropriate for the specific engine.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this an OEM component?\u003c\/summary\u003e\n  \u003cp\u003eNo. This is an aftermarket replacement impeller. The OEM and aftermarket numbers shown on this page are reference numbers for identification only.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eDo not rely on horsepower alone. Confirm the exact model, stroke type, serial number, and original part number.\u003c\/li\u003e\n  \u003cli\u003eDo not install this impeller if its dimensions, keyway, vane configuration, or reference markings differ from the original part without professional verification.\u003c\/li\u003e\n  \u003cli\u003eFollow the outboard manufacturer’s service manual and torque specifications.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended when lower-unit or water-pump service is unfamiliar.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMarine Replacement Parts\u003c\/strong\u003e — Practical aftermarket components for routine marine maintenance and repair.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication-Focused Listings\u003c\/strong\u003e — Product references and fitment information are provided to support careful part identification.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustomer Support\u003c\/strong\u003e — Contact support with your engine model, serial number, and original part information when application assistance is needed.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723786228027,"sku":"17IM007","price":15.18,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Water_Pump_Impeller_for_Mercury_15-50_HP_47-8508910_-_0755466_-_JLM_MARINE-8289726.jpg?v=1763031719"},{"product_id":"water-pump-repair-kit-fits-mercury-mariner-25-50hp-replaces-821354a2-821354a1","title":"Water Pump Impeller Repair Kit for Mercury\/Mariner 25–50 HP – Replaces 821354A2","description":"\u003csection\u003e\n\u003cstyle\u003e\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td { padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top; }\n  table.ss-table th { white-space:nowrap; word-break:normal; letter-spacing:normal; font-weight:600; background:#f8fafc; }\n  @media (max-width:480px){ table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; } }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003ewater pump impeller repair kit\u003c\/strong\u003e is designed for selected Mercury and Mariner outboard applications in the 25–50 HP range. It replaces Mercury OEM water pump repair kit reference \u003cstrong\u003e821354A2\u003c\/strong\u003e and is supplied without the water pump housing.\u003c\/p\u003e\n\u003cp\u003eThe kit renews the impeller and related water-pump service parts so an existing, serviceable housing can be rebuilt. Always confirm the engine model, stroke, gearcase configuration, and serial number before ordering.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAftermarket water pump repair kit for selected Mercury\/Mariner outboards.\u003c\/li\u003e\n  \u003cli\u003eReplaces Mercury OEM reference 821354A2.\u003c\/li\u003e\n  \u003cli\u003eIncludes an impeller, drive key, wear plate, gaskets, washers, and water tube seal.\u003c\/li\u003e\n  \u003cli\u003eHousing is not included; reuse the existing housing only if it is undamaged and within service limits.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number References\u003c\/h2\u003e\n\u003cp\u003eThe following references are provided for identification and cross-reference purposes. Part-number references do not replace engine-specific fitment verification.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number References\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand or Source\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e821354A2\u003c\/td\u003e\n\u003ctd\u003eOEM water pump repair kit reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-4531\u003c\/td\u003e\n\u003ctd\u003eWater pump repair kit reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eGLM\u003c\/td\u003e\n\u003ctd\u003e12045\u003c\/td\u003e\n\u003ctd\u003eImpeller service kit reference; verify component and application details before substitution\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\u003eThis kit is associated with selected Mercury and Mariner 25–50 HP applications using the 821354A2 water-pump configuration. Fitment varies by model, stroke, gear ratio, gearcase design, and serial-number range.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine and Model Compatibility\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel or Rating\u003c\/th\u003e\n\u003cth\u003eStroke \/ Configuration\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003cth\u003eSerial or Application Notes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury \/ Mariner\u003c\/td\u003e\n\u003ctd\u003e25–50 HP\u003c\/td\u003e\n\u003ctd\u003eSelected 2-stroke and 4-stroke applications\u003c\/td\u003e\n\u003ctd\u003e821354A2\u003c\/td\u003e\n\u003ctd\u003eVerify the exact engine model and serial number before purchase.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e30 HP, 2-cylinder\u003c\/td\u003e\n\u003ctd\u003eGear housing\/driveshaft applications\u003c\/td\u003e\n\u003ctd\u003e821354A2\u003c\/td\u003e\n\u003ctd\u003eCatalog records include multiple serial ranges, including 0G055314–0G760299, 0G760300–0T979999, 0T980000–0T999999, 1B000001 and up, 9854537–0P016999, 0P017000–0P325499, and 0P325500 and up.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e30 HP Jet, 3-cylinder\u003c\/td\u003e\n\u003ctd\u003eJet gearcase applications\u003c\/td\u003e\n\u003ctd\u003e821354A2\u003c\/td\u003e\n\u003ctd\u003eApplications include separate serial ranges and gear ratios; confirm the complete serial range and gearcase configuration.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 HP, 2- or 3-cylinder and Jet applications\u003c\/td\u003e\n\u003ctd\u003eSelected gear housing\/driveshaft applications\u003c\/td\u003e\n\u003ctd\u003e821354A2\u003c\/td\u003e\n\u003ctd\u003eMultiple serial ranges are cataloged; verify the exact model before ordering.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e The horsepower range alone is not sufficient to confirm fitment. Compare the existing water-pump parts and check the engine serial number against the applicable Mercury\/Mariner parts catalog.\u003c\/p\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eWater pump impeller repair kit\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n\u003cdd\u003eSelected Mercury\/Mariner 25–50 HP outboards\u003c\/dd\u003e\n  \u003cdt\u003eReplacement Reference\u003c\/dt\u003e\n\u003cdd\u003eMercury 821354A2\u003c\/dd\u003e\n  \u003cdt\u003eHousing\u003c\/dt\u003e\n\u003cdd\u003eNot included\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eService replacement for an existing compatible water pump assembly\u003c\/dd\u003e\n  \u003cdt\u003eBrand Status\u003c\/dt\u003e\n\u003cdd\u003eAftermarket replacement; not an OEM Mercury component\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × Water pump impeller\u003c\/li\u003e\n  \u003cli\u003e1 × Drive key\u003c\/li\u003e\n  \u003cli\u003e1 × Wear or face plate\u003c\/li\u003e\n  \u003cli\u003e1 × Upper water pump gasket, reference 27-822189\u003c\/li\u003e\n  \u003cli\u003e1 × Lower water pump gasket, reference 27-822217\u003c\/li\u003e\n  \u003cli\u003e2 × Washer, reference 12-866451\u003c\/li\u003e\n  \u003cli\u003e1 × Water tube seal\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eThe water pump housing, lower unit, driveshaft, fasteners, and lubricants are not included unless specifically listed above.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and follow the service manual for your specific engine.\u003c\/li\u003e\n  \u003cli\u003eSupport the outboard securely and remove the lower unit according to the manufacturer’s procedure.\u003c\/li\u003e\n  \u003cli\u003eRemove the water pump housing and note the impeller-vane direction before disassembly.\u003c\/li\u003e\n  \u003cli\u003eRemove the old impeller, key, gaskets, washers, wear plate, and water tube seal.\u003c\/li\u003e\n  \u003cli\u003eClean the mating surfaces and inspect the housing, wear plate, driveshaft, keyway, and water tube for damage or excessive wear.\u003c\/li\u003e\n  \u003cli\u003eInstall the new gasket, wear plate, drive key, impeller, remaining gasket, washers, and water tube seal in the same locations as the original parts.\u003c\/li\u003e\n  \u003cli\u003eUse a suitable water-based lubricant or mild soapy water during impeller installation. Do not use petroleum-based grease on the rubber impeller.\u003c\/li\u003e\n  \u003cli\u003eReinstall the pump housing while rotating the driveshaft in the correct direction to seat the vanes.\u003c\/li\u003e\n  \u003cli\u003eReinstall the lower unit and tighten all fasteners to the engine manufacturer’s specified torque.\u003c\/li\u003e\n  \u003cli\u003eRun the engine only in water or with an appropriate flushing device, and confirm a steady cooling-water tell-tale stream before normal operation.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eMaintenance \u0026amp; Troubleshooting\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I confirm that this kit fits my engine?\u003c\/summary\u003e\n  \u003cp\u003eMatch the engine brand, model, horsepower, stroke, gearcase configuration, and serial number with a parts catalog. The presence of 821354A2 on the old repair kit or parts diagram is the strongest identification clue. Do not rely on horsepower alone.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are common signs of a worn water pump impeller?\u003c\/summary\u003e\n  \u003cp\u003ePossible signs include a weak or intermittent tell-tale stream, overheating warnings, steam, or an impeller that is cracked, brittle, distorted, or missing vanes. Inspect the complete pump assembly when replacing the impeller.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes the kit include the water pump housing?\u003c\/summary\u003e\n  \u003cp\u003eNo. This is a repair kit without the housing. It is intended for installation in an existing compatible housing that is not damaged or excessively worn.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes it include the drive key and water tube seal?\u003c\/summary\u003e\n  \u003cp\u003eYes. The listed package contents include one drive key and one water tube seal, in addition to the impeller, wear plate, gaskets, and two washers.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should the impeller be replaced?\u003c\/summary\u003e\n  \u003cp\u003eInspect the impeller at the interval specified in the engine service manual and replace it whenever it shows wear, hardening, cracking, deformation, or damaged vanes. Service intervals may need to be shorter in saltwater, sandy, or silty operating conditions.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat if my serial number is not listed?\u003c\/summary\u003e\n  \u003cp\u003eDo not assume fitment. Use the full engine serial number and compare the pump assembly with the applicable parts diagram before ordering.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eRead and follow the engine manufacturer’s service instructions.\u003c\/li\u003e\n  \u003cli\u003eDisconnect the battery before beginning work and support the lower unit safely.\u003c\/li\u003e\n  \u003cli\u003eDo not operate the engine without an adequate water supply.\u003c\/li\u003e\n  \u003cli\u003eVerify the parts, dimensions, and package contents against the original assembly before installation.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement kit and is not manufactured by Mercury Marine.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMarine Replacement Parts\u003c\/strong\u003e — Practical aftermarket components for routine outboard service and repair.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication-Focused Information\u003c\/strong\u003e — Fitment references are provided to help customers compare engine and part-number details.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eService Support\u003c\/strong\u003e — Confirm model and serial-number information before installation for the best fit.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723806675259,"sku":"SIE-18KM007","price":25.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Water_Pump_Impeller_Kit_for_Mercury_25_-_30_-_40_-_45_-_50_HP_821354A2_-_JLM_MARINE-8290152.jpg?v=1763032271"},{"product_id":"boot-shift-shaft-fits-mercury-mercruiser-outboards-replaces-822158","title":"Boot Protector – Fits Mercury 25–50 HP Outboards (Replaces OEM 822158)","description":"\u003cstyle\u003e\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td { padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top; }\n  table.ss-table th { white-space:nowrap; word-break:normal; letter-spacing:normal; font-weight:600; background:#f8fafc; }\n  @media (max-width:480px){ table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; } }\n\u003c\/style\u003e\n\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis durable black rubber \u003cstrong\u003eboot protector\u003c\/strong\u003e is designed for the gear-housing and driveshaft assembly on a broad range of Mercury 25–50 HP outboard engines. It helps shield the protected shaft and surrounding gearcase area from water, dirt, and environmental contamination while providing a replacement for the original boot specified under Mercury OEM part number 822158.\u003c\/p\u003e\n  \u003cp\u003eThis is an aftermarket replacement component, not a genuine Mercury part. The catalog relationships available for OEM 822158 identify the part as a boot used in gear-housing and driveshaft diagrams. Always confirm your engine’s complete model and serial-number range before ordering.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eReplacement boot protector for selected Mercury outboard gear-housing applications.\u003c\/li\u003e\n    \u003cli\u003eBlack rubber construction suited to marine service conditions.\u003c\/li\u003e\n    \u003cli\u003eDesigned to help protect the covered shaft and gearcase area from water and debris.\u003c\/li\u003e\n    \u003cli\u003eSold as one individual boot; no seal kit or additional hardware is included.\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \u003ch2\u003ePart Number Reference\u003c\/h2\u003e\n  \u003cp\u003eUse the following reference to compare the replacement with your original component.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Part Number Reference\"\u003e\n      \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003ePart Number\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n      \u003ctbody\u003e\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n  \u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n  \u003cp\u003eThe catalog occurrences below associate OEM 822158 with the listed Mercury models and serial-number ranges. Horsepower, stroke, model designation, and serial range must be considered together; a horsepower match by itself does not confirm fitment.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Engine and Model Compatibility\"\u003e\n      \u003cthead\u003e\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\u003eOEM Part No.\u003c\/th\u003e\n\u003cth\u003eSerial Range\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e25 (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e25\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G590000–0G760299\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e25 (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e25\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G760300–0T408999\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e25 (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e25\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0T409000–1B344298\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e25 (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e25\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e9973100–0P016999; 0P017000–0P153499; 0P153500–0P388282\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e30 (2 Cyl.)\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003eStroke not specified in catalog occurrence\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G055314–0G760299; 0G760300–0T979999; 0T980000–0T999999; 1B000001 \u0026amp; Up; 9854537–0P016999; 0P017000–0P325499; 0P325500 \u0026amp; Up\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e30 JET (3 Cyl.)\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003eStroke not specified in catalog occurrence\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G590000–0G760299; 0G760300–0T408999; 9973100–0P016999; 0P017000–0P153499\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e30 EFI (3 Cyl.)\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0T409000–1B226999; 0P153500–0P400999\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 (2 Cyl.)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003eStroke not specified in catalog occurrence\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G055314–0G760299; 0G760300–0T979999; 0T980000–0T999999; 1B000001 \u0026amp; Up; 9854537–0P016999; 0P017000–0P325499; 0P325500 \u0026amp; Up\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 (3 Cyl.)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003eStroke not specified in catalog occurrence\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G760300–0T979999; 0T980000–1B209735; 9973100–0P016999; 0P017000–0P325499\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 JET\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003eStroke not specified in catalog occurrence\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0P325500 \u0026amp; Up\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G231123–0G760299; 0G760300–0T408999; 9944807–0P016999; 0P017000–0P153499\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 EFI (3 Cyl.) (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0T409000–1B226999; 1B227000–1B344398; 1C000001–1C043416\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 EFI (4 Cyl.) (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0P153500–0P400999; 0P401000–0P515896\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 CARB (3 Cyl.) (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e1B227000–1B344306; 1C000001–1C018825; 0P401000 \u0026amp; Up\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 Italy (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G760300–0T178499; 0P017000–0P094499\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e45 Bodensee (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e45\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G231123–0G760299; 0G760300–0T178499; 9944807–0P016999; 0P017000–0P094499\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e50 (3 Cyl.)\u003c\/td\u003e\n\u003ctd\u003e50\u003c\/td\u003e\n\u003ctd\u003eStroke not specified in catalog occurrence\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G590000–0G760299; 0G760300–0T979999; 0T980000 \u0026amp; Up; 9973100–0P016999; 0P017000–0P325499; 0P325500 \u0026amp; Up\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e50 Bigfoot (4-Stroke)\u003c\/td\u003e\n\u003ctd\u003e50\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e822158\u003c\/td\u003e\n\u003ctd\u003e0G231123–0G760299; 0G760300–0T178499; 9944807–0P016999; 0P017000–0P094499\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n  \u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eBoot protector\u003c\/dd\u003e\n    \u003cdt\u003eApplication\u003c\/dt\u003e\n\u003cdd\u003eGear housing and driveshaft assembly\u003c\/dd\u003e\n    \u003cdt\u003eReplacement Type\u003c\/dt\u003e\n\u003cdd\u003eAftermarket replacement for OEM 822158\u003c\/dd\u003e\n    \u003cdt\u003eMaterial\u003c\/dt\u003e\n\u003cdd\u003eRubber\u003c\/dd\u003e\n    \u003cdt\u003eColor\u003c\/dt\u003e\n\u003cdd\u003eBlack\u003c\/dd\u003e\n    \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003eLength: 2.50 in (63.5 mm); width: 1.75 in (44.45 mm); height: 1.25 in (31.75 mm)\u003c\/dd\u003e\n    \u003cdt\u003eWeight\u003c\/dt\u003e\n\u003cdd\u003e0.03 lb (13.6 g)\u003c\/dd\u003e\n    \u003cdt\u003eFitment Style\u003c\/dt\u003e\n\u003cdd\u003eSnug fit over the designated shaft or housing location\u003c\/dd\u003e\n    \u003cdt\u003eWarranty\u003c\/dt\u003e\n\u003cdd\u003e1 year against manufacturing defects under normal use\u003c\/dd\u003e\n    \u003cdt\u003eGTIN\u003c\/dt\u003e\n\u003cdd\u003e745061337046\u003c\/dd\u003e\n  \u003c\/dl\u003e\n  \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n  \u003cul\u003e\u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1 x\u003c\/span\u003e Boot protector\u003c\/li\u003e\u003c\/ul\u003e\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eTurn the engine off and follow the manufacturer’s service and safety procedures.\u003c\/li\u003e\n    \u003cli\u003eConfirm the engine model and serial number before disassembly.\u003c\/li\u003e\n    \u003cli\u003eAccess the gear-housing and driveshaft area; lower-unit or other component removal may be required depending on the engine.\u003c\/li\u003e\n    \u003cli\u003eRemove the old boot carefully and note its orientation and seating position.\u003c\/li\u003e\n    \u003cli\u003eClean the shaft and surrounding surfaces, removing dirt and deteriorated rubber.\u003c\/li\u003e\n    \u003cli\u003eInstall the replacement boot in the same orientation and ensure it is fully seated.\u003c\/li\u003e\n    \u003cli\u003eReassemble removed components and verify that the related mechanism operates correctly before returning the engine to service.\u003c\/li\u003e\n  \u003c\/ol\u003e\n  \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n  \u003cdetails\u003e\u003csummary\u003eHow do I confirm fitment?\u003c\/summary\u003e\u003cp\u003eCompare the engine brand, model designation, complete serial-number range, and the original part reference. OEM 822158 is associated with the Mercury applications listed above. Do not rely on horsepower alone.\u003c\/p\u003e\u003c\/details\u003e\n  \u003cdetails\u003e\u003csummary\u003eWhat are common signs that the boot needs replacement?\u003c\/summary\u003e\u003cp\u003eInspect for cracking, splitting, hardening, deformation, or a loose fit. A damaged or incorrectly seated boot may allow water and debris into the protected area and should be replaced promptly.\u003c\/p\u003e\u003c\/details\u003e\n  \u003cdetails\u003e\u003csummary\u003eCan I install this part myself?\u003c\/summary\u003e\u003cp\u003eInstallation may require partial lower-unit or gear-housing disassembly. It is suitable for an experienced technician familiar with Mercury outboard service procedures; professional installation is recommended when the required procedure is unfamiliar.\u003c\/p\u003e\u003c\/details\u003e\n  \u003cdetails\u003e\u003csummary\u003eHow often should it be inspected?\u003c\/summary\u003e\u003cp\u003eInspect the boot during routine annual service and whenever the lower unit or gearcase is serviced. Replace it at the first sign of deterioration.\u003c\/p\u003e\u003c\/details\u003e\n  \u003cdetails\u003e\u003csummary\u003eIs this an OEM Mercury part?\u003c\/summary\u003e\u003cp\u003eNo. This listing is for an aftermarket replacement boot protector that references Mercury OEM part number 822158 for identification and fitment comparison.\u003c\/p\u003e\u003c\/details\u003e\n  \u003cdetails\u003e\u003csummary\u003eShipping speed and cost\u003c\/summary\u003e\u003cp\u003eTypical transit is 5–15 days. Available shipping methods and delivery estimates are shown at checkout.\u003c\/p\u003e\u003c\/details\u003e\n  \u003cdetails\u003e\u003csummary\u003eWarranty and returns\u003c\/summary\u003e\u003cp\u003eThis product is covered by a 1-year warranty against manufacturing defects under normal use. Returns are subject to the applicable return policy and condition requirements.\u003c\/p\u003e\u003c\/details\u003e\n  \u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eVerify the model, stroke, serial range, original part, and installation position before ordering.\u003c\/li\u003e\n    \u003cli\u003eThis is an aftermarket replacement, not a genuine Mercury component.\u003c\/li\u003e\n    \u003cli\u003eDo not operate the engine if the boot is damaged, incorrectly fitted, or unable to seal the intended area.\u003c\/li\u003e\n    \u003cli\u003eProfessional installation is recommended when lower-unit or gear-housing disassembly is required.\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003ePro-Grade Standards — We supply marine replacement parts selected for demanding real-world service conditions.\u003c\/li\u003e\n    \u003cli\u003eFast Global Fulfillment — Standard delivery options are available to most regions.\u003c\/li\u003e\n    \u003cli\u003eManufacturer-Direct Value — Competitive pricing with attention to material quality and consistency.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723806708027,"sku":"23BS362","price":21.55,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23BS362_fe73e243-1883-4544-9f82-c205d467431f.jpg?v=1763032272"}],"url":"https:\/\/seasierra.com\/collections\/mercury-4-stroke-25-50hp-outboard-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}