{"title":"Mercury 2-Stroke Outboard Engine 20-300HP Parts","description":"\u003csection id=\"hero\" style=\"max-width: 960px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003cp\u003eThis page supports Mercury 2-Stroke outboard engines from 20–300HP. Use it to find compatible parts and routine service information, including maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse our main Mercury collection any time. 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\/section.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;padding:10px 16px;background:#0b5cab;color:#fff;text-decoration:none;border-radius:6px;\"\u003eBrowse All Mercury Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"max-width: 960px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eHow to Identify Your 20–300HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eFind the serial\/nameplate on the swivel bracket (port or starboard). The tag typically lists the serial number and may include a year code.\u003c\/li\u003e\n    \u003cli\u003eModel codes and suffixes: letters often indicate shaft length (S\/L\/XL), starting\/charging (M\/EL\/ELPT), and control type (tiller vs. remote). Note these details when selecting parts.\u003c\/li\u003e\n    \u003cli\u003ePlatform clues: 20–30HP are usually twin-cylinder; 40–90HP commonly inline‑3; 100–125HP inline‑4; 135–300HP V6 (carb\/EFI and some direct‑injected variants). Cylinder count and induction type affect plug count, carb\/EFI parts, and cooling components.\u003c\/li\u003e\n    \u003cli\u003eOil system: Determine if your engine is premix or oil‑injected (presence of a remote oil tank and an injection pump). This changes service procedures and certain parts.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"platforms\" style=\"max-width: 960px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003ePlatform Overview\u003c\/h2\u003e\n\n  \u003ch3\u003e20–30HP Twin-Cylinder 2‑Stroke\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;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\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‑2, carbureted 2‑Stroke; premix or oil‑injected depending on model\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003e20–30HP 2‑Stroke variants (e.g., EL\/ELPT options)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eLightweight, simple service, responsive at low to mid RPM\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eVerify premix vs. oil injection; cooling and ignition parts differ by year\/serial\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003e40–90HP Inline‑3 2‑Stroke\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;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\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, carbureted or oil‑injected 2‑Stroke\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003e40\/50\/60\/75\/90HP 2‑Stroke families (EL\/ELPTO variants)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eStrong mid‑range torque, good power‑to‑weight\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eFuel, ignition, and thermostat specs vary by serial group; match by serial for best results\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003e100–125HP Inline‑4 2‑Stroke\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;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\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‑4, carb or EFI 2‑Stroke depending on year\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003e100–125HP 2‑Stroke (remote control and power trim variants)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eSmooth operation, broad parts availability\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eIntake, ignition, and gearcase ratios can differ; verify by HP, serial, and shaft length\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003e135–300HP V6 2‑Stroke\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;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\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\u003eV6, carb\/EFI and some direct‑injected variants\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003e135\/150\/175\/200\/225\/250\/300HP 2‑Stroke families\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eHigh output with strong top‑end performance\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eDirect‑injected models use different fuel\/air hardware; match parts by serial and induction type\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: 960px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines for 2‑Stroke outboards. Always follow the procedures and schedules in your official service manual.\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;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\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 oil) and metal on the drain plug magnet\u003c\/td\u003e\n        \u003ctd\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\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd\u003eInspect 50 hours; replace 100 hours\/annual\u003c\/td\u003e\n        \u003ctd\u003eUse correct heat range and gap for your serial group\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 \/ inline filter\u003c\/td\u003e\n        \u003ctd\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd\u003eReplace sooner with stale\/contaminated fuel or storage use\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 or kit\u003c\/td\u003e\n        \u003ctd\u003eEvery 2 seasons or ~200 hours\u003c\/td\u003e\n        \u003ctd\u003eInspect telltale flow regularly; replace sooner for weak stream or overheat alarm\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 monthly in saltwater; replace at ~50% wear\u003c\/td\u003e\n        \u003ctd\u003eEnsure solid electrical contact; do not paint anodes\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      \u003ctr\u003e\n        \u003ctd\u003e2‑Stroke oil supply \/ injection check\u003c\/td\u003e\n        \u003ctd\u003eEach season\u003c\/td\u003e\n        \u003ctd\u003eVerify tank, lines, filters, and pump indexing; for premix, use manual‑specified ratio\u003c\/td\u003e\n        \u003ctd\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\u003eThermostat inspection\u003c\/td\u003e\n        \u003ctd\u003eEvery 2–3 seasons\u003c\/td\u003e\n        \u003ctd\u003eReplace if overheat, low temp, or prolonged idle issues occur\u003c\/td\u003e\n        \u003ctd\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\u003eLower unit seals (if contamination found)\u003c\/td\u003e\n        \u003ctd\u003eAs needed\u003c\/td\u003e\n        \u003ctd\u003eUse pressure\/vac test to confirm; reseal before gear damage occurs\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\u003ePropeller, cotter\/hardware\u003c\/td\u003e\n        \u003ctd\u003eInspect each trip; remove\/grease hub seasonally\u003c\/td\u003e\n        \u003ctd\u003eCheck for fishing line on shaft; verify correct pitch and WOT RPM\u003c\/td\u003e\n        \u003ctd\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=\"max-width: 960px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eRoutine Service — \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\u003eGearcase \u0026amp; 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\u003eFuel Filtration — \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\u003eCorrosion Protection — \u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\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  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"max-width: 960px; 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;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eWeak telltale \/ overheat alarm\u003c\/td\u003e\n        \u003ctd\u003eInspect intake screens, telltale hose, and thermostat; verify impeller age\u003c\/td\u003e\n        \u003ctd\u003eWater pump kit, thermostat, intake screen\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003ePoor acceleration or power loss\u003c\/td\u003e\n        \u003ctd\u003eCheck spark quality and plug condition; replace fuel filter; confirm compression\u003c\/td\u003e\n        \u003ctd\u003eSpark plugs, fuel filter, fuel pump diaphragm\/kit\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eHard starting \/ rough idle\u003c\/td\u003e\n        \u003ctd\u003eVerify choke\/enrichment operation; inspect for air leaks; clean carbs\u003c\/td\u003e\n        \u003ctd\u003eSpark plugs, carburetor repair kit, fuel lines\/primer bulb\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eExcessive smoke (2‑Stroke)\u003c\/td\u003e\n        \u003ctd\u003eConfirm oil ratio or oil‑injection calibration; check thermostat stuck open\u003c\/td\u003e\n        \u003ctd\u003eOil lines\/filters, injection pump service parts, thermostat\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGearcase noise \/ metal in gear oil\u003c\/td\u003e\n        \u003ctd\u003ePerform pressure\/vac test; inspect propshaft seal for fishing line damage\u003c\/td\u003e\n        \u003ctd\u003eLower unit seal kit, bearings\/gears (as required)\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: 960px; margin: 0 auto; padding: 16px;\"\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\u003eNot always. Mercury 2‑Stroke parts can differ by year, serial range, and platform (twin, inline‑3, inline‑4, V6). Match by serial number and configuration for best fit and performance.\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 every two seasons or ~200 hours, and sooner if the telltale weakens, the engine overheats, or you operate in sandy\/silty water.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should gear oil be changed?\u003c\/summary\u003e\n    \u003cp\u003eChange lower‑unit gear oil every 100 hours or annually. Inspect for water contamination (milky color) and metal on the drain plug magnet.\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 serial number, horsepower, approximate year, shaft length (S\/L\/XL), start\/trim options (M\/EL\/ELPT), and whether the engine is premix or oil‑injected.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"max-width: 960px; margin: 0 auto; padding: 16px;\"\u003e\n  \u003cp\u003eReady to find the right parts? Browse the main Mercury collection and filter by horsepower, year, and model to zero in on compatible items.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;padding:10px 16px;background:#0b5cab;color:#fff;text-decoration:none;border-radius:6px;\"\u003eShop Mercury Outboard Parts\u003c\/a\u003e\n  \u003cp style=\"margin-top:8px;color:#555;\"\u003eIf youre unsure about your model, send us a photo of the nameplate and the part you need and well help verify compatibility.\u003c\/p\u003e\n\u003c\/section\u003e","products":[],"url":"https:\/\/seasierra.com\/collections\/mercury-2-stroke-outboard-engine-20-300hp-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}