{"product_id":"straight-screw-plug-kit-fits-yamaha-40hp-300hp-replaces-688-45341-90340-08002-90430-08020","title":"Straight Screw Plug Kit – Fits Yamaha 40HP-300HP (Replaces 688-45341, 90340-08002, 90430-08020)","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 {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n  table.ss-table th {\n    white-space:nowrap;\n    word-break:normal;\n    letter-spacing:normal;\n    font-weight:600;\n    background:#f8fafc;\n  }\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eStraight Screw Plug Kit – Fits Yamaha 40HP-300HP\u003c\/strong\u003e is a complete lower unit drain and screw plug replacement package designed for most Yamaha outboard engines from 40HP to 300HP. Confirm fitment by matching your engine's part number, as not all models within this horsepower range use identical plug configurations.\u003c\/p\u003e\n\u003cp\u003eThis kit directly replaces OEM part numbers 688-45341, 90340-08002, and 90430-08020, along with superseded references including 688-45341-10-00, 90340-08002-00, 90430-08003.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eIncludes drain plug, straight screw plug, and two oil drain gaskets for a complete service\u003c\/li\u003e\n  \u003cli\u003eEssential for routine lower unit maintenance and oil changes\u003c\/li\u003e\n  \u003cli\u003eAlways buy by part number to ensure correct fitment\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e688-45341\u003c\/td\u003e\n        \u003ctd\u003eLower Unit Drain Plug\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e688-45341-10-00\u003c\/td\u003e\n        \u003ctd\u003eSuperseded reference\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e90340-08002\u003c\/td\u003e\n        \u003ctd\u003eStraight Screw Plug\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e90340-08002-00\u003c\/td\u003e\n        \u003ctd\u003eSuperseded reference\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e90430-08020\u003c\/td\u003e\n        \u003ctd\u003eLower Unit Oil Drain Gasket\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e90430-08003\u003c\/td\u003e\n        \u003ctd\u003eGasket interchange\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\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e40HP–300HP\u003c\/td\u003e\n        \u003ctd\u003e688-45341, 90340-08002, 90430-08020\u003c\/td\u003e\n        \u003ctd\u003eMost but not all engines in this range; buy by part number\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eLower unit drain and screw plug service\u003c\/dd\u003e\n  \u003cdt\u003eFitment Range\u003c\/dt\u003e\n  \u003cdd\u003eYamaha 40HP–300HP (verify by part number)\u003c\/dd\u003e\n  \u003cdt\u003eIncludes Gaskets\u003c\/dt\u003e\n  \u003cdd\u003eYes, 2× oil drain gaskets (90430-08020)\u003c\/dd\u003e\n  \u003cdt\u003eMaterial\u003c\/dt\u003e\n  \u003cdd\u003eCorrosion-resistant metal and elastomer seals\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1×\u003c\/strong\u003e Lower Unit Drain Plug \u003cem\u003e(688-45341)\u003c\/em\u003e\n\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1×\u003c\/strong\u003e Straight Screw Plug \u003cem\u003e(90340-08002)\u003c\/em\u003e\n\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e2×\u003c\/strong\u003e Lower Unit Oil Drain Gasket \u003cem\u003e(90430-08020)\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003ePosition the outboard vertically and allow the lower unit to cool completely.\u003c\/li\u003e\n  \u003cli\u003ePlace a catch pan beneath the drain plug to collect used gear oil.\u003c\/li\u003e\n  \u003cli\u003eRemove the old drain plug and straight screw plug using the appropriate socket or wrench.\u003c\/li\u003e\n  \u003cli\u003eInspect threads in the lower unit housing for damage or debris; clean if necessary.\u003c\/li\u003e\n  \u003cli\u003eInstall new gaskets onto the drain plug and screw plug; ensure they seat evenly.\u003c\/li\u003e\n  \u003cli\u003eThread each plug by hand first to avoid cross-threading, then snug to the manufacturer's torque specification.\u003c\/li\u003e\n  \u003cli\u003eRefill the lower unit with the correct grade and volume of gear oil per your service manual.\u003c\/li\u003e\n  \u003cli\u003eRun the engine briefly, then re-check for leaks around both plugs.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I confirm this kit fits my Yamaha outboard?\u003c\/summary\u003e\n  \u003cp\u003eCross-reference the part numbers on your current drain plug and screw plug against 688-45341, 90340-08002, or 90430-08020. Do not rely solely on horsepower rating, as some models within the 40–300HP range may use different configurations.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eCan I reuse the old gaskets?\u003c\/summary\u003e\n  \u003cp\u003eNo. Always replace drain gaskets during every oil change to ensure a proper seal and prevent leaks. This kit includes two new gaskets for that purpose.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat torque setting should I use for the drain plugs?\u003c\/summary\u003e\n  \u003cp\u003eConsult your Yamaha service manual for the exact torque specification. Over-tightening can strip threads or crack the housing; under-tightening risks leaks.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhy are there two gaskets in the kit?\u003c\/summary\u003e\n  \u003cp\u003eOne gasket is for the lower unit drain plug (688-45341) and one for the straight screw plug (90340-08002), ensuring complete sealing at both drain points.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should I replace these plugs and gaskets?\u003c\/summary\u003e\n  \u003cp\u003eReplace gaskets at every lower unit oil change—typically every 100 hours or annually. Inspect plugs for thread wear or corrosion and replace if damaged.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are signs that my drain plugs need replacement?\u003c\/summary\u003e\n  \u003cp\u003eVisible oil seepage around the plugs, stripped or rounded hex heads, corroded threads, or difficulty achieving proper torque all indicate it's time for new hardware.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n  \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images\/specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003ePro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003eFast Global Fulfillment — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003eManufacturer-Direct Value — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":51025914691899,"sku":"25GK074","price":16.14,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/12_c9bdaed9-43a6-4d6e-8e34-20646086b18c.jpg?v=1772975097","url":"https:\/\/seasierra.com\/products\/straight-screw-plug-kit-fits-yamaha-40hp-300hp-replaces-688-45341-90340-08002-90430-08020","provider":"SeaSierra","version":"1.0","type":"link"}