{"product_id":"intake-manifold-reed-block-gasket-fits-mercury-mariner-200hp-225hp-250hp-300hp-efi-dfi-optimax-replaces-27-804680-804680-27-841220-27-850283-850283","title":"Intake Manifold Reed Block Gasket – Fits Mercury Mariner 200HP 225HP 250HP 300HP EFI DFI Optimax (Replaces 27-804680, 804680, 27-841220, 27-850283, 850283)","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 Intake Manifold Reed Block Gasket is designed for Mercury Mariner 6-cylinder outboard engines, including 200HP, 225HP, 250HP, and 300HP models equipped with EFI, DFI, and Optimax fuel systems. Compatible with 3.0L and 3.2L displacement engines manufactured from 2000 through 2018, this gasket ensures a reliable seal between the reed block and intake manifold assembly.\u003c\/p\u003e\n\u003cp\u003eThis aftermarket replacement directly interchanges with Mercury OEM part numbers 27-804680, 804680, 27-841220, 27-850283, and 850283.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eSeals the reed block to intake manifold interface\u003c\/li\u003e\n  \u003cli\u003eCompatible with EFI, DFI, and Optimax fuel injection systems\u003c\/li\u003e\n  \u003cli\u003eFits Mercury Pro XS and XS series engines\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\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003ePrimary OEM reference\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e804680\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e27-841220\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e27-850283\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e850283\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\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\u003eModel\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eYears\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMariner\u003c\/td\u003e\n        \u003ctd\u003eALL\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e27-804680\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 3L EFI\u003c\/td\u003e\n        \u003ctd\u003e200\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2002–2008\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.625 Bore 3L EFI\u003c\/td\u003e\n        \u003ctd\u003e225\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2002–2008\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.625 Bore 3L EFI\u003c\/td\u003e\n        \u003ctd\u003e250\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2002–2008\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\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2006–2017\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.6265 Bore 3L Optimax\u003c\/td\u003e\n        \u003ctd\u003e200\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2000–2018\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.6265 Bore 3L Optimax\u003c\/td\u003e\n        \u003ctd\u003e225\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2000–2018\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.6265 Bore 3L Optimax\u003c\/td\u003e\n        \u003ctd\u003e250\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2008–2014\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.6265 Bore 3L Pro XS\u003c\/td\u003e\n        \u003ctd\u003e200\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2008–2018\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.6265 Bore 3L Pro XS\u003c\/td\u003e\n        \u003ctd\u003e225\u003c\/td\u003e\n        \u003ctd\u003e27-804680\u003c\/td\u003e\n        \u003ctd\u003e2005–2018\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e6 Cyl 3.6265 Bore 3L Pro XS\u003c\/td\u003e\n        \u003ctd\u003e250\u003c\/td\u003e\n        \u003ctd\u003e27-804680\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\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003ePart Type\u003c\/dt\u003e\n  \u003cdd\u003eIntake Manifold Reed Block Gasket\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eMercury Mariner 200HP – 300HP EFI \/ DFI \/ Optimax\u003c\/dd\u003e\n  \u003cdt\u003eEngine Configuration\u003c\/dt\u003e\n  \u003cdd\u003e6-Cylinder\u003c\/dd\u003e\n  \u003cdt\u003eDisplacement\u003c\/dt\u003e\n  \u003cdd\u003e3.0L \/ 3.2L\u003c\/dd\u003e\n  \u003cdt\u003eFuel System\u003c\/dt\u003e\n  \u003cdd\u003eEFI, DFI, Optimax\u003c\/dd\u003e\n  \u003cdt\u003eOEM Reference\u003c\/dt\u003e\n  \u003cdd\u003e27-804680, 804680, 27-841220, 27-850283, 850283\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003cstrong\u003e1 × Gasket\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and relieve fuel system pressure before beginning work.\u003c\/li\u003e\n  \u003cli\u003eRemove the intake manifold assembly to access the reed block.\u003c\/li\u003e\n  \u003cli\u003eClean all mating surfaces thoroughly, removing old gasket material and residue.\u003c\/li\u003e\n  \u003cli\u003eInspect the reed block and manifold for cracks, warping, or damage before reassembly.\u003c\/li\u003e\n  \u003cli\u003ePosition the new gasket on the reed block, aligning all bolt holes.\u003c\/li\u003e\n  \u003cli\u003eReinstall the intake manifold, torquing bolts to manufacturer specifications in a crisscross pattern.\u003c\/li\u003e\n  \u003cli\u003eReconnect fuel lines and electrical connections securely.\u003c\/li\u003e\n  \u003cli\u003ePerform a pressure test or visual inspection for leaks before returning the engine to service.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eHow do I know if my reed block gasket needs replacement?\u003c\/summary\u003e\u003cp\u003eCommon signs include rough idling, loss of power, fuel odor, poor acceleration, or visible fuel leaks around the intake manifold. A failed gasket can cause air leaks that affect fuel mixture and engine performance.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan I reuse the old gasket during reassembly?\u003c\/summary\u003e\u003cp\u003eNo. Reed block gaskets are designed for single use and compress permanently when torqued. Reusing an old gasket will result in improper sealing and potential vacuum leaks.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs this gasket compatible with both DFI and Optimax systems?\u003c\/summary\u003e\u003cp\u003eYes. This gasket fits Mercury 3.0L and 3.2L engines with EFI, DFI, and Optimax fuel injection systems across the model years listed in the compatibility table.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat torque specification should I use for the intake manifold bolts?\u003c\/summary\u003e\u003cp\u003eConsult your Mercury service manual for exact torque specifications, as values vary by model year. Typically, intake manifold bolts require sequential torquing in a crisscross pattern to ensure even gasket compression.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWill this fit a 3.0L EFI 200HP from 2002?\u003c\/summary\u003e\u003cp\u003eYes. This gasket is compatible with Mercury 6-cylinder 3.0L EFI 200HP, 225HP, and 250HP engines from 2002 through 2008.\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\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":51025915281723,"sku":"3460","price":20.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/12_a335af82-9d80-434e-9efb-cc8bf6cab6bb.jpg?v=1773220552","url":"https:\/\/seasierra.com\/products\/intake-manifold-reed-block-gasket-fits-mercury-mariner-200hp-225hp-250hp-300hp-efi-dfi-optimax-replaces-27-804680-804680-27-841220-27-850283-850283","provider":"SeaSierra","version":"1.0","type":"link"}