{"product_id":"fuel-pump-diaphragm-kit-fits-mercury-mariner-70-115-hp-replaces-42909a1-42909a2-42909a3-42909a4","title":"Fuel Pump Diaphragm Kit – Fits Mercury Mariner 70-115 HP (Replaces 42909A1, 42909A2, 42909A3, 42909A4)","description":"\u003csection\u003e\n\u003c!-- 🔧 Table Styles (include only once per page) --\u003e\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\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eFuel Pump Diaphragm Kit\u003c\/strong\u003e is designed for Mercury Mariner 70–115 HP outboard engines, specifically fitting 3-cylinder (70, 75, 80, 90 HP) and 4-cylinder (100, 115 HP) models manufactured between 1983–1993.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct cross-reference for Mercury part numbers 42909A1, 42909A2, 42909A3, and 42909A4, and interchanges with Sierra 18-7818-1, Mallory 9-37754, and GLM 40280.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eDirect replacement fit for straightforward installation.\u003c\/li\u003e\n\u003cli\u003eEngineered for use with standard gasoline fuel systems.\u003c\/li\u003e\n\u003cli\u003eCompatible with models equipped with a 90-degree oil check valve on the pump cover.\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 suppliers.\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\u003e42909A1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e42909A2\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e42909A3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e42909A4\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-7818-1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMallory\u003c\/td\u003e\n        \u003ctd\u003e9-37754\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGLM\u003c\/td\u003e\n        \u003ctd\u003e40280\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 and year in the table below to ensure accurate fitment.\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\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\u003e3-cylinder\u003c\/td\u003e\n        \u003ctd\u003e70\u003c\/td\u003e\n        \u003ctd\u003e1983–1990\u003c\/td\u003e\n        \u003ctd\u003e42909A1\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e3-cylinder\u003c\/td\u003e\n        \u003ctd\u003e75\u003c\/td\u003e\n        \u003ctd\u003e1987–1993\u003c\/td\u003e\n        \u003ctd\u003e42909A1\u003c\/td\u003e\n        \u003ctd\u003eModels with 90-degree oil check valve on pump cover\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e3-cylinder\u003c\/td\u003e\n        \u003ctd\u003e80\u003c\/td\u003e\n        \u003ctd\u003e1987–1990\u003c\/td\u003e\n        \u003ctd\u003e42909A1\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e3-cylinder\u003c\/td\u003e\n        \u003ctd\u003e90\u003c\/td\u003e\n        \u003ctd\u003e1987–1993\u003c\/td\u003e\n        \u003ctd\u003e42909A1\u003c\/td\u003e\n        \u003ctd\u003eModels with 90-degree oil check valve on pump cover\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e4-cylinder\u003c\/td\u003e\n        \u003ctd\u003e100\u003c\/td\u003e\n        \u003ctd\u003e1988–1993\u003c\/td\u003e\n        \u003ctd\u003e42909A3\u003c\/td\u003e\n        \u003ctd\u003eModels with 90-degree oil check valve on pump cover\/white fuel pump body\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e4-cylinder\u003c\/td\u003e\n        \u003ctd\u003e115\u003c\/td\u003e\n        \u003ctd\u003e1988–1993\u003c\/td\u003e\n        \u003ctd\u003e42909A3\u003c\/td\u003e\n        \u003ctd\u003eModels with white fuel pump body\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\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eFuel Pump Diaphragm Kit\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n  \u003cdt\u003eFuel Type\u003c\/dt\u003e\n\u003cdd\u003eGasoline\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eCompatible with 90-degree oil check valve models\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Diaphragm (replaces 42909A1, 42909A2, 42909A3, 42909A4)\u003c\/li\u003e\n  \u003cli\u003e1 x Gasket (replaces 987691)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cp\u003eFor a safe and effective installation, disconnect the battery and relieve all fuel system pressure before beginning work. Clean the fuel pump housing and cover surfaces thoroughly to remove any old gasket material or debris. Install the new diaphragm and gasket, ensuring correct orientation. Tighten all fasteners evenly to the manufacturer's recommended torque specifications to prevent leaks. After reassembly, prime the fuel system and carefully inspect for any signs of fuel leakage before starting the engine.\u003c\/p\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if my fuel pump diaphragm is failing?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs of a faulty diaphragm include the engine failing to start, stalling unexpectedly, sputtering or losing power at high speeds, or visible fuel leaks around the fuel pump housing.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this kit compatible with my specific engine?\u003c\/summary\u003e\n  \u003cp\u003eThis kit is designed for a specific range of Mercury\/Mariner engines from 1983–1993. It is critical to consult the compatibility table and pay close attention to notes regarding the number of cylinders, the presence of a 90-degree oil check valve, or the color of the fuel pump body to ensure a correct match.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the difference between the 42909A1, A2, A3, and A4 part numbers?\u003c\/summary\u003e\n  \u003cp\u003eThese numbers typically represent successive revisions or updates from the original equipment manufacturer. This aftermarket diaphragm kit is designed to be a universal replacement that covers all of these superseded part numbers.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhen should a fuel pump diaphragm be replaced?\u003c\/summary\u003e\n  \u003cp\u003eWhile there is no fixed service interval, it is recommended to inspect the fuel system components annually. You should replace the diaphragm immediately if you notice any signs of wear, brittleness, cracking, or fuel leakage to prevent fuel delivery issues and potential engine damage.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this an OEM part?\u003c\/summary\u003e\n  \u003cp\u003eThis is a high-quality aftermarket replacement part, not an OEM component. It is engineered to meet or exceed original equipment specifications for fit, form, and function and is produced in an ISO 9002 certified facility to ensure consistent quality.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow fast is shipping?\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide, with most orders arriving in 5–15 days via standard shipping. Standard delivery is free, and expedited options are available at checkout for most regions.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the warranty and return policy?\u003c\/summary\u003e\n  \u003cp\u003eThis product is covered by a 1-year warranty against manufacturing defects under normal operating conditions. If you encounter an issue, please contact our support team with your order details. Returns of unused items in their original condition are accepted within our standard return window. Please see our full policy page or contact us 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 and specifications against your original part before purchase. If anything differs—even if your model is listed as compatible—do not order.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement part, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is strongly recommended for safety and optimal performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world reliability.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — We offer free standard delivery to most regions with an average transit time of 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50718257119547,"sku":"23CR486","price":9.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Fuel_Pump_Diaphragm_Kit_for_Mercury_70_75_80_90_115_HP_42909A1_-_JLM_MARINE-8285748.jpg?v=1763039295","url":"https:\/\/seasierra.com\/products\/fuel-pump-diaphragm-kit-fits-mercury-mariner-70-115-hp-replaces-42909a1-42909a2-42909a3-42909a4","provider":"SeaSierra","version":"1.0","type":"link"}