{"product_id":"new-aftermarket-yamaha-115-130hp-2-4-stroke-outboard-lower-unit-90-405","title":"New Aftermarket Yamaha 115-130HP 2-4-Stroke Outboard Lower Unit 90-405","description":"\u003cp data-start=\"426\" data-end=\"871\"\u003eThe \u003cstrong data-start=\"430\" data-end=\"472\"\u003eSEI 90-405 Yamaha 115–130HP lower unit\u003c\/strong\u003e is a brand-new, high-quality \u003cstrong data-start=\"502\" data-end=\"529\"\u003eaftermarket replacement\u003c\/strong\u003e designed for both \u003cstrong data-start=\"548\" data-end=\"597\"\u003e2-stroke and 4-stroke Yamaha outboard engines\u003c\/strong\u003e from \u003cstrong data-start=\"603\" data-end=\"619\"\u003e1984 to 2014\u003c\/strong\u003e. Built to OEM specifications, it provides smooth shifting, durable performance, and dependable reliability. Available in \u003cstrong data-start=\"741\" data-end=\"770\"\u003e20″ and 25″ shaft lengths\u003c\/strong\u003e, this \u003cstrong data-start=\"777\" data-end=\"809\"\u003estandard rotation lower unit\u003c\/strong\u003e ensures a perfect fit for a wide range of Yamaha outboards.\u003c\/p\u003e\n\n\n\u003chr data-start=\"873\" data-end=\"876\"\u003e\n\n\u003ch2 data-start=\"878\" data-end=\"899\"\u003e\u003cstrong data-start=\"881\" data-end=\"897\"\u003eKey Features\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cul data-start=\"900\" data-end=\"1392\"\u003e\n \t\u003cli data-start=\"900\" data-end=\"988\"\u003e\n\u003cp data-start=\"902\" data-end=\"988\"\u003e100% brand-new \u003cstrong data-start=\"917\" data-end=\"960\"\u003eaftermarket Yamaha 115–130HP lower unit\u003c\/strong\u003e – no core return required\u003c\/p\u003e\n\u003c\/li\u003e\n \t\u003cli data-start=\"989\" data-end=\"1060\"\u003e\n\u003cp data-start=\"991\" data-end=\"1060\"\u003eDesigned for \u003cstrong data-start=\"1004\" data-end=\"1036\"\u003eYamaha 2-stroke and 4-stroke\u003c\/strong\u003e outboards (1984–2014)\u003c\/p\u003e\n\u003c\/li\u003e\n \t\u003cli data-start=\"1061\" data-end=\"1122\"\u003e\n\u003cp data-start=\"1063\" data-end=\"1122\"\u003eBuilt for \u003cstrong data-start=\"1073\" data-end=\"1094\"\u003estandard rotation\u003c\/strong\u003e (right-hand) applications\u003c\/p\u003e\n\u003c\/li\u003e\n \t\u003cli data-start=\"1123\" data-end=\"1189\"\u003e\n\u003cp data-start=\"1125\" data-end=\"1189\"\u003eGear ratios: \u003cstrong data-start=\"1138\" data-end=\"1156\"\u003e2:1 (2-Stroke)\u003c\/strong\u003e and \u003cstrong data-start=\"1161\" data-end=\"1187\"\u003e2.15:1 (F115 4-Stroke)\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n \t\u003cli data-start=\"1190\" data-end=\"1252\"\u003e\n\u003cp data-start=\"1192\" data-end=\"1252\"\u003ePainted \u003cstrong data-start=\"1200\" data-end=\"1209\"\u003eblack\u003c\/strong\u003e and can be repainted to match OEM finish\u003c\/p\u003e\n\u003c\/li\u003e\n \t\u003cli data-start=\"1253\" data-end=\"1324\"\u003e\n\u003cp data-start=\"1255\" data-end=\"1324\"\u003eManufactured with precision components for long-lasting performance\u003c\/p\u003e\n\u003c\/li\u003e\n \t\u003cli data-start=\"1325\" data-end=\"1392\"\u003e\n\u003cp data-start=\"1327\" data-end=\"1392\"\u003eProtected by an \u003cstrong data-start=\"1343\" data-end=\"1390\"\u003eindustry-leading 3-year fault-free warranty\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr data-start=\"1394\" data-end=\"1397\"\u003e\n\n\u003ch2 data-start=\"1399\" data-end=\"1420\"\u003e\u003cstrong data-start=\"1402\" data-end=\"1420\"\u003eSpecifications\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cdiv class=\"_tableContainer_1rjym_1\"\u003e\n\u003cdiv class=\"group _tableWrapper_1rjym_13 flex w-fit flex-col-reverse\" tabindex=\"-1\"\u003e\n\u003ctable class=\"w-fit min-w-(--thread-content-width)\" data-start=\"1422\" data-end=\"1894\"\u003e\n\u003cthead data-start=\"1422\" data-end=\"1451\"\u003e\n\u003ctr data-start=\"1422\" data-end=\"1451\"\u003e\n\u003cth data-start=\"1422\" data-end=\"1436\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1424\" data-end=\"1435\"\u003eFeature\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth data-start=\"1436\" data-end=\"1451\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1438\" data-end=\"1449\"\u003eDetails\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody data-start=\"1483\" data-end=\"1894\"\u003e\n\u003ctr data-start=\"1483\" data-end=\"1509\"\u003e\n\u003ctd data-start=\"1483\" data-end=\"1495\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1485\" data-end=\"1494\"\u003eModel\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1495\" data-end=\"1509\"\u003eSEI 90-405\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1510\" data-end=\"1548\"\u003e\n\u003ctd data-start=\"1510\" data-end=\"1533\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1512\" data-end=\"1532\"\u003eHorsepower Range\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1533\" data-end=\"1548\"\u003e115HP–130HP\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1549\" data-end=\"1590\"\u003e\n\u003ctd data-start=\"1549\" data-end=\"1567\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1551\" data-end=\"1566\"\u003eEngine Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1567\" data-end=\"1590\"\u003e2-Stroke \u0026amp; 4-Stroke\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1591\" data-end=\"1631\"\u003e\n\u003ctd data-start=\"1591\" data-end=\"1606\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1593\" data-end=\"1605\"\u003eRotation\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1606\" data-end=\"1631\"\u003eStandard (Right-Hand)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1632\" data-end=\"1668\"\u003e\n\u003ctd data-start=\"1632\" data-end=\"1655\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1634\" data-end=\"1654\"\u003eCompatible Years\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1655\" data-end=\"1668\"\u003e1984–2014\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1669\" data-end=\"1702\"\u003e\n\u003ctd data-start=\"1669\" data-end=\"1689\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1671\" data-end=\"1688\"\u003eShaft Lengths\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1689\" data-end=\"1702\"\u003e20″ \u0026amp; 25″\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1703\" data-end=\"1763\"\u003e\n\u003ctd data-start=\"1703\" data-end=\"1721\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1705\" data-end=\"1720\"\u003eGear Ratios\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1721\" data-end=\"1763\"\u003e2:1 (2-Stroke), 2.15:1 (F115 4-Stroke)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1764\" data-end=\"1818\"\u003e\n\u003ctd data-start=\"1764\" data-end=\"1782\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1766\" data-end=\"1781\"\u003ePaint Color\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1782\" data-end=\"1818\"\u003eBlack (repaintable to match OEM)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1819\" data-end=\"1844\"\u003e\n\u003ctd data-start=\"1819\" data-end=\"1834\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1821\" data-end=\"1833\"\u003eWarranty\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1834\" data-end=\"1844\"\u003e3-Year\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"1845\" data-end=\"1894\"\u003e\n\u003ctd data-start=\"1845\" data-end=\"1857\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"1847\" data-end=\"1856\"\u003eBrand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-col-size=\"sm\" data-start=\"1857\" data-end=\"1894\"\u003eSEI (Sterndrive Engineering Inc.)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003chr data-start=\"1896\" data-end=\"1899\"\u003e\n\n\u003ch2 data-start=\"1901\" data-end=\"1965\"\u003e\u003cstrong data-start=\"1904\" data-end=\"1963\"\u003eWhy Choose the Yamaha 115–130HP Aftermarket Lower Unit?\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp data-start=\"1966\" data-end=\"2240\"\u003eThe \u003cstrong data-start=\"1970\" data-end=\"2013\"\u003eYamaha 115–130HP aftermarket lower unit\u003c\/strong\u003e from SEI offers the perfect combination of \u003cstrong data-start=\"2057\" data-end=\"2096\"\u003eperformance, reliability, and value\u003c\/strong\u003e. Each unit is built entirely from \u003cstrong data-start=\"2131\" data-end=\"2149\"\u003enew components\u003c\/strong\u003e, not remanufactured or rebuilt parts, ensuring consistent strength and smooth operation.\u003c\/p\u003e\n\u003cp data-start=\"2242\" data-end=\"2506\"\u003eDesigned as a direct replacement for OEM Yamaha lower units, the SEI 90-405 meets or exceeds factory standards. It’s a cost-effective alternative that maintains the same precision fit, gear alignment, and overall quality expected from original Yamaha assemblies.\u003c\/p\u003e\n\u003cp data-start=\"2508\" data-end=\"2786\"\u003eWith its \u003cstrong data-start=\"2517\" data-end=\"2545\"\u003e3-year no-fault warranty\u003c\/strong\u003e, this lower unit provides peace of mind and unmatched protection. Whether replacing a damaged unit or upgrading for better reliability, this \u003cstrong data-start=\"2687\" data-end=\"2730\"\u003eaftermarket \u003ca href=\"https:\/\/yamahaoutboards.com\/\"\u003eYamaha\u003c\/a\u003e 115–130HP lower unit\u003c\/strong\u003e is the professional’s choice for lasting performance.\u003c\/p\u003e\n\n\n\u003chr data-start=\"1896\" data-end=\"1899\"\u003e\n\n\u003csection id=\"faq\"\u003e\n\u003ch2\u003eFrequently Asked Questions – Yamaha 115–130HP Replacement Lower Unit\u003c\/h2\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003ch3\u003e1. Which Yamaha outboard models are compatible with the SEI 90-405 115–130HP lower unit?\u003c\/h3\u003e\nThe SEI 90-405 lower unit is engineered for Yamaha 115HP to 130HP outboards produced from 1984 to 2014, supporting both 2-stroke and 4-stroke engines. It fits standard rotation outboards and is available for 20″ (long) and 25″ (extra-long) shaft lengths. Specific compatibility includes popular 2-stroke and 4-stroke F115 models, but does not fit newer outboards outside the listed range.\n\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003ch3\u003e2. What gear ratios are offered for this aftermarket lower unit, and how do I select the right one?\u003c\/h3\u003e\nThis SEI replacement lower unit is available in two gear ratios: 2:1 for standard Yamaha 2-stroke models, and 2.15:1 for the F115 4-stroke model. To ensure optimal performance and correct propeller speed, match the gear ratio to your outboard’s original specification as indicated in your owner's manual or service documentation.\n\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003ch3\u003e3. Is this lower unit new, rebuilt, or remanufactured?\u003c\/h3\u003e\nThe SEI 90-405 lower unit is 100% brand new, built from all-new components — not rebuilt, not remanufactured, and no core return is required. Each assembly is thoroughly pressure-tested for quality and comes pre-assembled with all critical internals, ensuring consistent durability from the moment of installation.\n\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003ch3\u003e4. Does this lower unit come with a warranty, and what does it cover?\u003c\/h3\u003e\nYes, every SEI 90-405 Yamaha 115–130HP lower unit includes an industry-leading 3-Year Fault-Free Warranty. This comprehensive warranty covers defects in materials and workmanship as well as mechanical failures under normal use, providing peace of mind for recreational boaters and professionals alike.\n\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003ch3\u003e5. What preparation is needed for installation, and is the unit painted?\u003c\/h3\u003e\nThe unit is shipped painted in black for corrosion resistance, and it can be repainted to match the factory Yamaha color. Before installation, fill the lower unit with the correct marine gear oil—units are shipped dry. Also, verify shaft length and gear ratio compatibility with your current outboard setup for seamless installation.\n\n\u003c\/div\u003e\n\u003c\/section\u003e\n\n\u003chr data-start=\"2788\" data-end=\"2791\"\u003e\n\n\u003ch3 data-start=\"2793\" data-end=\"2834\"\u003e\u003cstrong data-start=\"2797\" data-end=\"2832\"\u003eExplore More Yamaha Lower Units\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-start=\"2835\" data-end=\"2924\"\u003e\u003ca href=\"https:\/\/allboatsupplies.com\/outboard-lower-unit\/yamaha\/\"\u003eBrowse All Yamaha Lower Unit Categories \u003c\/a\u003e  — find compatible options for 40HP, 60HP, 115HP, 150HP, and more Yamaha outboards.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Which Yamaha outboard models are compatible with the SEI 90-405 115–130HP lower unit?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"This SEI 90-405 unit fits Yamaha 115HP to 130HP outboards manufactured from 1984 to 2014 for both 2-stroke and 4-stroke engines, including models like the F115. It suits both 20″ and 25″ shaft lengths and standard (right-hand) rotation, but does not fit models beyond these years.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What gear ratios are offered for this aftermarket lower unit, and how do I select the right one?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"The lower unit comes with either a 2:1 ratio for Yamaha 2-stroke models or a 2.15:1 ratio for F115 4-stroke. Always match the ratio with your outboard's original specification to ensure proper operation.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is this lower unit new, rebuilt, or remanufactured?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"This SEI 90-405 unit is entirely new and not rebuilt or remanufactured. There is no core deposit, and every assembly is factory-tested and pre-assembled with all key internal components.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Does this lower unit come with a warranty, and what does it cover?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes, the lower unit includes a 3-Year Fault-Free Warranty covering manufacturing defects and mechanical failures under normal use for complete peace of mind.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"What preparation is needed for installation, and is the unit painted?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"The lower unit is shipped painted in black for corrosion protection and may be repainted to match OEM colors. It must be filled with marine gear oil before use, and compatibility for shaft length and gear ratio must be confirmed during the install process.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"All Marine Suppliers","offers":[{"title":"2:1 Ratio \/ 20\" Shaft \/ 2 Stroke \/ RH Rotation","offer_id":47822941520131,"sku":"SE90-405-A20","price":1195.0,"currency_code":"USD","in_stock":true},{"title":"2:1 Ratio \/ 25\" Shaft \/ 2 Stroke \/ RH Rotation","offer_id":47822941552899,"sku":"SE90-405-A25","price":1195.0,"currency_code":"USD","in_stock":true},{"title":"2.15:1 Ratio \/ 20\" Shaft \/ 4 Stroke \/ RH Rotation","offer_id":47822941585667,"sku":"SE90-405-B20F","price":1195.0,"currency_code":"USD","in_stock":true},{"title":"2.15:1 Ratio \/ 25\" Shaft \/ 4 Stroke \/ RH Rotation","offer_id":47822941618435,"sku":"SE90-405-B25F","price":1195.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0808\/2613\/8883\/files\/4a7c13d3-1-1.png?v=1772820578","url":"https:\/\/allmarinesuppliers.com\/products\/new-aftermarket-yamaha-115-130hp-2-4-stroke-outboard-lower-unit-90-405","provider":"All Marine Suppliers","version":"1.0","type":"link"}