{"title":"Mercury 4-Stroke 2.5-3.5HP Outboard Engine Parts","description":"\u003csection id=\"hero\" style=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003cp\u003eThis page is dedicated to Mercury 4‑Stroke 2.5–3.5HP outboard engines. Use it to find compatible parts and practical service information, including maintenance tips, frequently replaced items, and troubleshooting guidance. You can also browse the main Mercury collection, and at the bottom of this page you’ll find links to start browsing parts for this engine. On the collection page, use the “Filter \u0026amp; Sort” controls to narrow results by horsepower, year range, and part category.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block; padding:10px 16px; background:#1b5e20; color:#fff; text-decoration:none; border-radius:4px;\"\u003eBrowse All Mercury Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eHow to Identify Your 2.5–3.5HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eFind the serial\/nameplate on the transom bracket or swivel bracket. Record the full serial number and any model suffix.\u003c\/li\u003e\n    \u003cli\u003eModel code suffixes commonly indicate shaft length (short vs. long) and control type (tiller\/manual start). Verify this against your engine’s features.\u003c\/li\u003e\n    \u003cli\u003eThese portable 4‑Stroke models are typically carbureted, single‑cylinder, manual‑start tiller engines. Many service parts are shared between 2.5HP and 3.5HP.\u003c\/li\u003e\n    \u003cli\u003eWhen in doubt, match parts by serial range; small changes by year can affect gaskets, jets, and hardware.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eEngine Overview\u003c\/h2\u003e\n  \u003ch3\u003eMercury 2.5HP \u0026amp; 3.5HP 4‑Stroke Platform\u003c\/h3\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eSingle‑cylinder, carbureted 4‑Stroke, manual start, tiller steer; short and long shaft variants.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003e2.5HP and 3.5HP portable outboards (short\/long shaft). Many service items interchange between both HP ratings.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eLightweight, easy to handle, simple maintenance, quiet and fuel‑efficient operation for tenders and small craft.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eImpeller\/water pump service kits and many tune‑up parts are shared across 2.5\/3.5HP; verify by serial for year‑specific parts.\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=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines for small 4‑Stroke portable outboards. Always consult your official Mercury service manual for procedures and exact specifications for your serial range.\u003c\/p\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eEngine oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eAfter first 10 hrs, then every 50–100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eMost 2.5\/3.5HP models do not use a replaceable oil filter; change oil more frequently in heavy use.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\"\u003eMercury Outboard Parts\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eEvery 100 hrs or annually; inspect after groundings\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eCheck for water or metal on drain plug; replace seals if contamination is found.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\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 style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eSpark plug\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eInspect every 100 hrs; replace as needed or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eUse correct heat range and gap for your serial range; fouling indicates mixture\/fuel issues.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\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 style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eFuel filter \/ inline screen\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eInspect every 100 hrs or each season\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eReplace if restricted or contaminated; stale fuel is a common cause of carb issues.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\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 style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eWater pump impeller \/ kit\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eEvery 2 seasons or 200 hrs (sooner if weak tell‑tale)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eCritical for cooling on shallow\/sandy launches; renew housing if scored.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\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 style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eAnodes (sacrificial)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eInspect each season; replace when 50% depleted\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eEssential in salt\/brackish water; match material (zinc\/aluminum\/magnesium) to your waters.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\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\u003c\/section\u003e\n\n\u003csection id=\"common-parts\" style=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eRoutine Service \u0026amp; Tune‑Up: \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\"\u003eMercury Outboard Parts\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\u003eLower Unit \u0026amp; Sealing: \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\u003eFuel System Filtration: \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eIgnition \u0026amp; Spark: \u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003eSpark Plugs\u003c\/a\u003e • \u003ca href=\"https:\/\/seasierra.com\/collections\/electrical-items\"\u003eElectrical Items\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003ePropulsion\/Hardware: \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e • \u003ca href=\"https:\/\/seasierra.com\/collections\/propeller-guards\"\u003ePropeller Guards\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=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eWeak tell‑tale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eInspect intake screens for blockage; verify impeller condition and thermostat operation.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eWater pump impeller kit, pump housing, intake screen, thermostat\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eHard starting or stalls at idle\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eUse fresh fuel; check choke operation; inspect plug gap and condition; look for clogged idle circuit.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eSpark plug, carburetor gasket\/jet set, fuel filter, primer bulb\/fuel line\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003ePoor acceleration \/ lacks power\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eConfirm prop is correct and undamaged; check for fouled plug or restricted fuel flow; verify throttle linkage.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003ePropeller and shear\/cotter pin, spark plug, fuel filter, fuel pump, carburetor kit\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eGearcase noise or milky gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eInspect magnetic drain plug for metal; check for water intrusion; pressure test gearcase if needed.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f0f0f0;\"\u003eLower unit seal kit, drain\/fill gaskets, prop shaft seal, carrier seal\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=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre 2.5HP and 3.5HP parts interchangeable?\u003c\/summary\u003e\n    \u003cp\u003eMany routine service parts (impeller kits, some gaskets, and ignition items) are shared across the 2.5HP and 3.5HP 4‑Stroke platform. Verify by serial number for year‑specific fuel and carb components.\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 preventative measure, replace the impeller every 2 seasons or about 200 hours. Replace sooner if the tell‑tale is weak, you run in sandy\/shallow water, or if the pump housing is scored.\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 annually or every 100 hours, whichever comes first. Inspect immediately after any prop strike or grounding; contaminated oil indicates the need for new seals.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information helps confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003ePlease provide the engine’s serial number, shaft length (short\/long), and a clear photo of the nameplate. For carb\/fuel parts, details about the year and any modifications are helpful.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"max-width: 980px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003cp\u003eReady to find parts by horsepower, year, and model? Browse the main Mercury collection to get started.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block; padding:10px 16px; background:#1b5e20; color:#fff; text-decoration:none; border-radius:4px;\"\u003eShop Mercury Outboard Parts\u003c\/a\u003e\n  \u003cp style=\"margin-top:8px; color:#555;\"\u003eIf you’re unsure about your model, send us a clear 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-kit-fits-mercury-mariner-tohatsu-2-5-3-5-hp-replaces-8m0181314-47-161543-369-65021-1-309-65021-1","title":"Water Pump Impeller Service Kit for Mercury\/Mariner and Tohatsu 2.5–3.5 HP 4-Stroke Outboards – Replaces 8M0181314, 47-161543, 369-65021-1 and 309-65021-1","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 service kit\u003c\/strong\u003e is intended for selected Mercury\/Mariner and Tohatsu 2.5 HP and 3.5 HP 4-stroke outboard applications. The Mercury\/Mariner applications are Tohatsu-based engines, so confirm the exact model and serial-number range before ordering.\u003c\/p\u003e\n\u003cp\u003eThe kit is associated with Mercury references \u003cstrong\u003e8M0181314\u003c\/strong\u003e and \u003cstrong\u003e47-161543\u003c\/strong\u003e, plus Tohatsu references \u003cstrong\u003e369-65021-1\u003c\/strong\u003e and \u003cstrong\u003e309-65021-1\u003c\/strong\u003e. These numbers are included as identification and cross-reference information; always compare the original impeller and the engine parts diagram before installation.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIncludes an impeller, water-pump gaskets, an impeller key and two gearbox drain\/fill screw fibre washers.\u003c\/li\u003e\n  \u003cli\u003eDesigned for routine water-pump service on compatible small outboards.\u003c\/li\u003e\n  \u003cli\u003eSuitable for freshwater and saltwater service when installed and maintained correctly.\u003c\/li\u003e\n  \u003cli\u003eAftermarket replacement; not an original Mercury, Mariner or Tohatsu-branded kit.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse the following references to compare the replacement with the part listed for your engine.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Cross-Reference\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eReference\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\u003e8M0181314\u003c\/td\u003e\n\u003ctd\u003eService-kit reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e47-161543\u003c\/td\u003e\n\u003ctd\u003eImpeller\/service reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003e369-65021-1\u003c\/td\u003e\n\u003ctd\u003eWater-pump impeller reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003e309-65021-1\u003c\/td\u003e\n\u003ctd\u003eWater-pump impeller reference used in other applications\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\u003eFitment must be confirmed by engine brand, model, horsepower, stroke and serial number together. The references above also appear in other Tohatsu applications, including some 2-stroke models, so a part-number match by itself is not sufficient.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel family\u003c\/th\u003e\n\u003cth\u003eRated HP\u003c\/th\u003e\n\u003cth\u003eStroke\u003c\/th\u003e\n\u003cth\u003eApplication notes\u003c\/th\u003e\n\u003cth\u003eRelated reference\u003c\/th\u003e\n\u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eF2.5\u003c\/td\u003e\n        \u003ctd\u003e2.5\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003eSelected Tohatsu-manufactured applications; verify serial number before purchase.\u003c\/td\u003e\n        \u003ctd\u003e8M0181314 \/ 47-161543\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eF3.5\u003c\/td\u003e\n        \u003ctd\u003e3.5\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003eSelected Tohatsu-manufactured applications; verify serial number before purchase.\u003c\/td\u003e\n        \u003ctd\u003e8M0181314 \/ 47-161543\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eTohatsu\u003c\/td\u003e\n        \u003ctd\u003eMFS2.5 \/ MFS3.5\u003c\/td\u003e\n        \u003ctd\u003e2.5 \/ 3.5\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003eCatalog occurrences identify the impeller reference in the MFS2\/MFS2.5\/MFS3.5B family. Confirm the exact year and parts diagram.\u003c\/td\u003e\n        \u003ctd\u003e369-65021-1\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 Do not use this listing for a 2-stroke engine unless your engine's parts diagram specifically confirms the same complete service-kit contents and application. The same impeller references are cataloged across multiple engine families with different fitment conditions.\u003c\/p\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eAftermarket water pump impeller service kit\u003c\/dd\u003e\n  \u003cdt\u003ePrimary Service\u003c\/dt\u003e\n\u003cdd\u003eOutboard lower-unit water-pump maintenance\u003c\/dd\u003e\n  \u003cdt\u003eImpeller Material\u003c\/dt\u003e\n\u003cdd\u003eNeoprene rubber with a molded hub\u003c\/dd\u003e\n  \u003cdt\u003eImpeller Reference\u003c\/dt\u003e\n\u003cdd\u003e369-65021-1 \/ 309-65021-1\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eReplacement installation using standard marine service tools\u003c\/dd\u003e\n  \u003cdt\u003eFitment Type\u003c\/dt\u003e\n\u003cdd\u003eApplication-specific aftermarket replacement\u003c\/dd\u003e\n  \u003cdt\u003eStroke Coverage\u003c\/dt\u003e\n\u003cdd\u003e4-stroke Mercury\/Mariner and Tohatsu applications listed above; verify before ordering\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  \u003cli\u003e1 x Water pump gasket, reference 3F0-65018-0\u003c\/li\u003e\n  \u003cli\u003e1 x Water pump gasket, reference 3F0-65029-0\u003c\/li\u003e\n  \u003cli\u003e1 x Impeller key, reference 369-65022-0\u003c\/li\u003e\n  \u003cli\u003e2 x Gearbox drain\/fill screw fibre washers, reference 332-60006-0\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the spark-plug lead and follow the engine manufacturer's safety instructions.\u003c\/li\u003e\n  \u003cli\u003ePlace a drain pan under the gearcase. Remove the drain and fill screws and drain the gear oil if required by the service procedure.\u003c\/li\u003e\n  \u003cli\u003eRemove the bolts securing the lower unit to the midsection and carefully lower the unit.\u003c\/li\u003e\n  \u003cli\u003eRemove the water-pump housing to expose the old impeller.\u003c\/li\u003e\n  \u003cli\u003eClean the housing, base plate and mating surfaces. Remove all old gasket material and debris.\u003c\/li\u003e\n  \u003cli\u003eInstall the new key, gaskets and impeller in the correct order. Follow the engine service manual for vane orientation and tightening torque.\u003c\/li\u003e\n  \u003cli\u003eReinstall the pump housing and lower unit. Refill the gearcase with the specified lubricant and inspect the screw washers for proper sealing.\u003c\/li\u003e\n  \u003cli\u003eRun the engine only in water or with an appropriate flushing device, then confirm a steady tell-tale stream and check for leaks or overheating.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003e\u003cstrong\u003eInstallation warning:\u003c\/strong\u003e Incorrect impeller orientation, missing gaskets, debris in the pump housing or running the engine without a water supply can cause overheating and engine damage.\u003c\/p\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I confirm fitment for my engine?\u003c\/summary\u003e\n  \u003cp\u003eCheck the brand, exact model designation, horsepower, stroke and serial number against the engine parts diagram. For the listed Mercury\/Mariner and Tohatsu 4-stroke applications, also compare the original impeller and the applicable reference number before ordering.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this kit fit every 2.5 HP or 3.5 HP outboard?\u003c\/summary\u003e\n  \u003cp\u003eNo. Horsepower alone does not confirm fitment. The same or related impeller references appear in multiple Tohatsu model families and in both 2-stroke and 4-stroke catalog applications. Confirm the complete engine identification and service-kit contents.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhen should the water-pump impeller be replaced?\u003c\/summary\u003e\n  \u003cp\u003eReplace it according to the engine manufacturer's maintenance schedule and inspect it whenever cooling-water flow is weak, the tell-tale stops flowing, or an overheating warning occurs. Replace it sooner after operation in sand, silt or heavy saltwater exposure.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a worn or damaged impeller?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs include a weak or absent tell-tale stream, overheating, an overheating alarm or visible cracking and deformation when the pump is inspected. Stop operating the engine if cooling flow is abnormal.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this an OEM kit?\u003c\/summary\u003e\n  \u003cp\u003eNo. This is an aftermarket replacement kit supplied for compatible applications. The Mercury, Mariner and Tohatsu references are shown for identification and cross-reference purposes.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is included compared with an original service kit?\u003c\/summary\u003e\n  \u003cp\u003eThis listing includes the impeller, listed water-pump gaskets, impeller key and two gearbox drain\/fill screw fibre washers. Contents of original-branded service kits may differ, so compare the package list before ordering.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow should I store the replacement impeller?\u003c\/summary\u003e\n  \u003cp\u003eKeep it sealed, clean and away from direct sunlight, ozone, petroleum products and excessive heat until installation. Do not install an impeller that is cracked, permanently deformed or contaminated.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify the engine's exact model, year or production range, stroke and serial number before purchase.\u003c\/li\u003e\n  \u003cli\u003eCompare the original part and all kit components with the package list.\u003c\/li\u003e\n  \u003cli\u003eNever run an outboard without an adequate water supply.\u003c\/li\u003e\n  \u003cli\u003eUse the engine service manual for torque values, gear-oil requirements and final testing.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended when lower-unit service is unfamiliar.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement and is not manufactured or packaged by Mercury, Mariner or Tohatsu.\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 components for routine maintenance and repair.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication-focused listings\u003c\/strong\u003e — Product references and fitment conditions are provided to help customers compare before ordering.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSupport for maintenance work\u003c\/strong\u003e — Always use the manufacturer's service information for final installation and safety procedures.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723791896891,"sku":"23KM770","price":46.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23KM770_1_a2fa708e-2112-4826-8210-e912b37d2963.jpg?v=1763031898"}],"url":"https:\/\/seasierra.com\/collections\/mercury-4-stroke-2-5-3-5hp-outboard-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}