{"product_id":"thermostat-130-f-54-c-fits-mercury-mariner-200-300hp-replaces-885599003-885599004-8m0057307","title":"Thermostat (130°F\/54°C) – Fits Mercury\/Mariner 200-300HP (Replaces 885599003, 885599004, 8M0057307)","description":"\n\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\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\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\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\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis is a replacement \u003cstrong\u003eThermostat (130°F\/54°C)\u003c\/strong\u003e designed for a wide range of Mercury and Mariner 200-300 HP V6 engines, including EFI, DFI, Optimax, Pro XS, and XS models manufactured between 2002 and 2017. It ensures your engine maintains the correct operating temperature for optimal performance and fuel efficiency.\u003c\/p\u003e\n  \u003cp\u003eIt serves as a direct replacement for Mercury OEM parts 885599003, 885599004, and 8M0057307, as well as aftermarket equivalents like Sierra 18-3535 and WSM 775-15.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eInstalls as a direct OEM-equivalent replacement.\u003c\/li\u003e\n    \u003cli\u003eRegulates engine temperature by opening at 130°F (54°C).\u003c\/li\u003e\n    \u003cli\u003eIncludes one thermostat per package.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\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        \u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e885599003\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e885599004\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e8M0057307\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eSierra\u003c\/td\u003e\n          \u003ctd\u003e18-3535\u003c\/td\u003e\n        \u003c\/tr\u003e\n         \u003ctr\u003e\n          \u003ctd\u003eWSM\u003c\/td\u003e\n          \u003ctd\u003e775-15\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n  \u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n  \u003cp\u003eThis thermostat is designed for various 6-cylinder Mercury and Mariner outboards from 200 HP to 300 HP.\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\u003eModel\u003c\/th\u003e\n          \u003cth\u003eRated HP\u003c\/th\u003e\n          \u003cth\u003eStroke\u003c\/th\u003e\n          \u003cth\u003eYears\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\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.625 Bore 3.0L EFI\u003c\/td\u003e\n          \u003ctd\u003e225\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2002–2003\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.625 Bore 3.0L EFI\u003c\/td\u003e\n          \u003ctd\u003e250\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2006–2008\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.625 Bore 3.0L XB\u003c\/td\u003e\n          \u003ctd\u003e250\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2002–2003\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.6265 Bore 3.2L XS\u003c\/td\u003e\n          \u003ctd\u003e300\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2006–2017\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.6265 Bore 3.0L Optimax\u003c\/td\u003e\n          \u003ctd\u003e200\u003c\/td\u003e\n          \u003ctd\u003e2-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2003–2006\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.6265 Bore 3.0L Optimax\u003c\/td\u003e\n          \u003ctd\u003e250\u003c\/td\u003e\n          \u003ctd\u003e2-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2009–2014\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eMercury\u003c\/td\u003e\n          \u003ctd\u003e6 Cyl 3.6265 Bore 3.0L Pro XS\u003c\/td\u003e\n          \u003ctd\u003e225\u003c\/td\u003e\n          \u003ctd\u003e2-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2004–2010\u003c\/td\u003e\n          \u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e200 DFI 3.0L\u003c\/td\u003e\n\u003ctd\u003e200\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e(serial OG386496-Up)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e225 HP 3.0L Carb \u0026amp; EFI\u003c\/td\u003e\n\u003ctd\u003e225\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e(serial OD280813-Up)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e225 DFI\u003c\/td\u003e\n\u003ctd\u003e225\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e(serial OG129222-Up)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e250 3.0L EFI\u003c\/td\u003e\n\u003ctd\u003e250\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e(serial OG1219222-Up)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e225XS \/ Sport XS \/ Pro XS\u003c\/td\u003e\n\u003ctd\u003e225\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e250XS \/ Sport XS \/ Pro XS\u003c\/td\u003e\n\u003ctd\u003e250\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e300X\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e300XS\u003c\/td\u003e\n\u003ctd\u003e300\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e885599003, 885599004, 8M0057307\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\n\n\u003csection\u003e\n  \u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eEngine Thermostat\u003c\/dd\u003e\n    \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect OEM Replacement\u003c\/dd\u003e\n    \u003cdt\u003eTemperature Rating\u003c\/dt\u003e\n\u003cdd\u003e130°F (54°C)\u003c\/dd\u003e\n    \u003cdt\u003eOperating Temperature\u003c\/dt\u003e\n\u003cdd\u003e130°F (54°C) open temperature\u003c\/dd\u003e\n    \u003cdt\u003eWarranty\u003c\/dt\u003e\n\u003cdd\u003eManufacturer dependent (typically 1 year)\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e1 x Thermostat (885599003\/885599004\/8M0057307)\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eDisconnect the battery before beginning work.\u003c\/li\u003e\n    \u003cli\u003eAllow the engine to cool completely.\u003c\/li\u003e\n    \u003cli\u003eDrain the engine coolant into a suitable container.\u003c\/li\u003e\n    \u003cli\u003eLocate the thermostat housing on the engine and remove the cover.\u003c\/li\u003e\n    \u003cli\u003eRemove the old thermostat and any gasket material.\u003c\/li\u003e\n    \u003cli\u003eClean the housing and cover surfaces thoroughly.\u003c\/li\u003e\n    \u003cli\u003eInstall the new thermostat, ensuring it is correctly oriented. Use a new gasket if required.\u003c\/li\u003e\n    \u003cli\u003eReinstall the thermostat housing cover and tighten bolts to the manufacturer's recommended torque.\u003c\/li\u003e\n    \u003cli\u003eRefill the cooling system with the appropriate coolant.\u003c\/li\u003e\n    \u003cli\u003eReconnect the battery, start the engine, and check for any leaks as it warms up.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eHow do I know if my thermostat is failing?\u003c\/summary\u003e\u003cp\u003eCommon signs of a faulty thermostat include engine overheating, temperature gauge reading irregularly (too high or too low), and poor engine performance. If the thermostat is stuck open, the engine may not reach its optimal operating temperature. If stuck closed, it will overheat.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs a gasket included with this thermostat?\u003c\/summary\u003e\u003cp\u003eThis listing is for the thermostat only. Gaskets are sold separately. It is highly recommended to replace the gasket during thermostat installation to ensure a proper seal.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan I use a different temperature thermostat?\u003c\/summary\u003e\u003cp\u003eIt is critical to use the thermostat with the OEM-specified temperature rating for your engine. Using a thermostat with a different temperature can lead to improper engine performance, increased emissions, and potential engine damage.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow often should a marine thermostat be replaced?\u003c\/summary\u003e\u003cp\u003eWhile there is no fixed interval, it is good practice to inspect the thermostat during routine cooling system service (e.g., every 2-3 years or 200-300 hours) and replace it if there are signs of corrosion or if it fails a function test.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\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\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eShipping speed \u0026amp; cost?\u003c\/summary\u003e\u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWarranty \u0026amp; returns?\u003c\/summary\u003e\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\u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eVerify images\/specifications vs 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\u003c\/section\u003e\n\n\u003csection\u003e\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\n\u003c\/section\u003e\n","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723797041467,"sku":"23TH607","price":25.48,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/885599003_1_79ff49c0-0b24-42ff-b886-0ffd9bdc15c3.jpg?v=1763031999","url":"https:\/\/seasierra.com\/products\/thermostat-130-f-54-c-fits-mercury-mariner-200-300hp-replaces-885599003-885599004-8m0057307","provider":"SeaSierra","version":"1.0","type":"link"}