{"title":"EMP 25HP Outboard Marine Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px; border:1px solid #e5e7eb; border-radius:8px;\"\u003e\n  \u003cp\u003eThis page is dedicated to EMP 25HP outboard engines. Use it to find compatible parts and service information, including maintenance tips, common replacement items, and troubleshooting guidance. You can also browse the main EMP collection to see more options. Scroll to the bottom of the page 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\/propellers\" style=\"display:inline-block; margin-top:8px; padding:10px 14px; background:#0ea5e9; color:#fff; text-decoration:none; border-radius:6px;\"\u003eBrowse All EMP Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eHow to Identify Your 25HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eNameplate\/serial plate: Look on the transom bracket or swivel bracket for the model and serial number. On some engines it’s on the side of the clamp bracket or a sticker on the midsection.\u003c\/li\u003e\n    \u003cli\u003eModel code and suffix: The letters often indicate shaft length (S\/L\/XL), control type (tiller\/remote), and revision year. Note these when selecting parts.\u003c\/li\u003e\n    \u003cli\u003eStroke type cues: 4‑stroke models have an engine oil dipstick and filler cap; 2‑stroke models may be premix or oil‑injected and will not have a crankcase oil filter.\u003c\/li\u003e\n    \u003cli\u003eGearcase\/spline: Many 25–30HP models use a small 3\" gearcase with a 10‑spline propshaft. Verify splines and hub style before ordering a propeller or hub components.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"margin-top:24px;\"\u003e\n  \u003ch2\u003ePlatform Overview\u003c\/h2\u003e\n  \u003ch3\u003eLegacy 25HP 2‑Stroke (typical 1980s–2000s)\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 #e5e7eb; padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #e5e7eb; 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 #f3f4f6;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eInline‑2, carbureted 2‑Stroke; small 3\" gearcase; commonly 10‑spline prop shaft.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eGeneral 25HP 2‑Stroke models (various years). Often premix 50:1 or oil‑injected.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eLightweight, simple to service, strong hole‑shot for their size.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eProp pitch selection is critical; many applications fall in ~9–14\" pitch depending on load and hull. Verify spline count and thru‑hub exhaust before ordering props.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eModern 25–30HP 4‑Stroke (2000s–Newer)\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 #e5e7eb; padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #e5e7eb; 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 #f3f4f6;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eInline‑3, carb or EFI 4‑Stroke; many use a 3\" gearcase with 10‑spline prop shaft on non‑“BigFoot”\/non‑“Command Thrust” versions.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e25\/30HP non‑BigFoot\/standard gearcase; some variants labeled BigFoot\/Command Thrust use a larger gearcase and different prop families.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eLow noise, improved fuel economy, steady trolling, good mid‑range torque.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eConfirm gearcase type (standard vs. larger “BigFoot\/CT”) before selecting a propeller. Match pitch to WOT RPM target for your hull and load.\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=\"margin-top:24px;\"\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 service manual for your exact model and operating conditions.\u003c\/p\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left; padding:8px; border-bottom:1px solid #e5e7eb;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left; padding:8px; border-bottom:1px solid #e5e7eb;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left; padding:8px; border-bottom:1px solid #e5e7eb;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left; padding:8px; border-bottom:1px solid #e5e7eb;\"\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 #f3f4f6;\"\u003eEngine oil \u0026amp; filter (4‑Stroke)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eUse marine oil and the correct filter grade; change more often for heavy duty or dusty use.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\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 style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eCheck for water intrusion and metal on the drain plug magnet. Replace seals if contamination is found.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/lower-unit-seal-kits\"\u003eLower 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 #f3f4f6;\"\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eInspect gap and insulator color; replace if fouled or worn to maintain crisp starts.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\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 #f3f4f6;\"\u003eFuel filter \/ water separator\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eReplace more often with ethanol fuel or if debris is found. Keep a spare onboard.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\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 #f3f4f6;\"\u003eWater pump impeller \/ kit\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e2 years or 200 hours\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eShorten interval for sandy\/silty water or weak tell‑tale stream.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/water-pump-impeller-rebuild-kits\"\u003eWater Pump Impeller Rebuild Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eAnodes (sacrificial)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eInspect every 50 hours; replace as needed\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eUse the correct alloy for fresh vs. saltwater. Maintain good electrical bonding.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e2‑Stroke oiling (if applicable)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eEvery outing \/ seasonal check\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eUse correct premix ratio (often 50:1) or service oil‑injection tank, lines, and filter; purge air after service.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/popular\"\u003ePopular\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003ePropeller inspection\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eEvery 50–100 hours\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eRemove and check for fishing line at the seals; verify pitch suits your WOT RPM range under load.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\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=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eCooling system service: \u003ca href=\"https:\/\/seasierra.com\/collections\/water-pump-impeller-rebuild-kits\"\u003eWater Pump Impeller Rebuild Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eLower unit service: \u003ca href=\"https:\/\/seasierra.com\/collections\/lower-unit-seal-kits\"\u003eLower Unit Seal Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eFuel system upkeep: \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eIgnition tune‑up: \u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003eSpark Plugs\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    \u003cli\u003eProp selection \u0026amp; upgrades: \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eElectrical diagnostics: \u003ca href=\"https:\/\/seasierra.com\/collections\/electrical-items\"\u003eElectrical Items\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"margin-top:24px;\"\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; padding:8px; border-bottom:1px solid #e5e7eb;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left; padding:8px; border-bottom:1px solid #e5e7eb;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left; padding:8px; border-bottom:1px solid #e5e7eb;\"\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 #f3f4f6;\"\u003eWeak tell‑tale stream \/ overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eInspect intake screens for debris; verify impeller condition; check thermostat operation.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eWater pump kit, thermostat, intake screen\/grommets\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003ePoor acceleration or can’t reach WOT RPM\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eCheck prop for damage or wrong pitch; inspect fuel filter; verify spark plug condition and gap.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003ePropeller, fuel filter, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eHard starting \/ rough idle\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eReplace stale fuel; inspect primer bulb and lines; clean\/replace plugs; check idle speed settings.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eFuel filter, fuel hose\/bulb, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eExcessive smoke (2‑Stroke)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eConfirm premix ratio or oil pump setting; ensure choke\/enrichment isn’t stuck; check for flooded carb.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #f3f4f6;\"\u003eCarburetor parts, fuel system service, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eGearcase noise \/ metal in gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eDrain and inspect gear oil; check for fishing line on propshaft seals; pressure test lower unit.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eLower unit seal kit, gear oil service parts, 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=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre parts interchangeable between different years or platforms?\u003c\/summary\u003e\n    \u003cp\u003eSome service parts are shared, but many items depend on year, stroke type, and gearcase variant (standard vs. larger gearcase). Always confirm your model code, serial number, gearcase size, and prop shaft spline count.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should I replace the impeller?\u003c\/summary\u003e\n    \u003cp\u003eAs a rule of thumb, replace the impeller every 2 years or ~200 hours—sooner if you boat in sandy or silty water, see a weak tell‑tale stream, or after any overheat.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should the lower unit gear oil be changed?\u003c\/summary\u003e\n    \u003cp\u003eChange gear oil every 100 hours or annually. Inspect for water intrusion (milky oil) and metal on the drain plug magnet. If contamination is present, replace the prop shaft and driveshaft seals.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information helps confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003eProvide the model code, serial number, shaft length (S\/L\/XL), control type (tiller\/remote), prop shaft spline count, and your current prop diameter\/pitch and WOT RPM results.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"margin:24px 0; padding:16px; border:1px solid #e5e7eb; border-radius:8px;\"\u003e\n  \u003cp\u003eReady to find parts by horsepower, year, and model? Browse our main collection and filter to your 25HP application.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\" style=\"display:inline-block; margin-top:8px; padding:10px 14px; background:#0ea5e9; color:#fff; text-decoration:none; border-radius:6px;\"\u003eBrowse Collection\u003c\/a\u003e\n  \u003cp style=\"margin-top:8px; color:#374151;\"\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":[],"url":"https:\/\/seasierra.com\/collections\/emp-25hp-outboard-marine-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}