{"product_id":"mercury-mercruiser-diaphragm-kit-55278a1","title":"Mercury MerCruiser Quicksilver Diaphragm Kit 55278A1","description":"\u003ch2\u003eMercury Quicksilver Diaphragm Kit – Part No. 55278A1\u003c\/h2\u003e\n\n\u003cp\u003eThis is a genuine OEM Mercury Marine \/ Quicksilver diaphragm kit for MerCruiser carbureted engine applications. Diaphragm kits in this part number range are used in fuel pump assemblies, choke pull-off mechanisms, and vacuum-operated carburetor components on carbureted MerCruiser sterndrive and inboard engines. The \u003cstrong\u003eA1\u003c\/strong\u003e suffix designates the current revised kit specification. A failed or hardened diaphragm is a common cause of fuel delivery problems, hard starting, and rough running on carbureted engines — replacing the diaphragm kit restores proper fuel pump stroke or choke operation without replacing the entire assembly.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003ePart Details\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 55278A1\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Mercury Marine \/ Quicksilver\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOfficial Product Type:\u003c\/strong\u003e Diaphragm Kit\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRevision:\u003c\/strong\u003e A1 — current production specification\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Fuel System — carburetor or fuel pump assembly\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e New OEM\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eCompatible Applications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eMerCruiser carbureted sterndrive and inboard engines — specific assembly varies by model and serial number range\u003c\/li\u003e\n  \u003cli\u003eFuel pump diaphragm replacement on carbureted engine packages\u003c\/li\u003e\n  \u003cli\u003eChoke pull-off or vacuum diaphragm replacement on Rochester and MerCarb carburetors\u003c\/li\u003e\n  \u003cli\u003eVerify fitment using the Mercury parts diagram, carburetor model, and engine serial number before ordering\u003c\/li\u003e\n  \u003cli\u003eNot applicable to EFI or MPI fuel-injected engines\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eKit Contents\u003c\/h2\u003e\n\u003cp\u003eContents vary by application but typically include one or more diaphragm membranes and associated sealing components. Confirm kit contents against the Mercury parts diagram for your specific assembly before ordering.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eRelieve fuel system pressure and disconnect the fuel supply before disassembly\u003c\/li\u003e\n  \u003cli\u003eNote the orientation of the diaphragm before removal — incorrect orientation will prevent proper operation\u003c\/li\u003e\n  \u003cli\u003eClean all mating surfaces and inspect the housing for cracks or corrosion before installing the new diaphragm\u003c\/li\u003e\n  \u003cli\u003eReplace all gaskets and seals disturbed during disassembly\u003c\/li\u003e\n  \u003cli\u003eFollow the Mercury service manual for reassembly sequence and torque specifications\u003c\/li\u003e\n  \u003cli\u003eCheck for leaks and verify correct operation before returning the engine to service\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eService Interval\u003c\/h2\u003e\n\u003cp\u003eInspect the diaphragm during annual carburetor service or any time fuel delivery problems, hard starting, or rough running are present. Replace immediately if the diaphragm shows cracking, hardening, pinhole leaks, or loss of flexibility. Diaphragms degrade over time from fuel exposure and heat cycling even without visible damage — replacement during a carburetor overhaul is recommended as a matter of course.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eBest use case:\u003c\/strong\u003e Annual carburetor service, fuel pump rebuild, or targeted diagnosis of fuel delivery problems on carbureted MerCruiser engines. This kit is the correct path when the diaphragm is the failed component and the housing is still serviceable — significantly less expensive than replacing the entire fuel pump or carburetor assembly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCommon mistakes:\u003c\/strong\u003e Ordering a diaphragm kit without confirming the carburetor or fuel pump model — Mercury used several different diaphragm specifications across Rochester, MerCarb, and fuel pump assemblies that are not interchangeable. Also confirm the engine is carbureted: EFI and MPI engines do not use diaphragm-type fuel pumps or choke pull-offs. If the diaphragm has failed due to ethanol fuel damage, inspect the entire carburetor for related deterioration before reassembly.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eRelated Parts\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/mercury-mercruiser-2-barrel-carburetor-repair-kit-823427a1\"\u003eMercury MerCruiser 2-Barrel Carburetor Repair Kit 823427A1\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/mercury-mercruiser-carburetor-fuel-filter-35-53336q\"\u003eMercury MerCruiser Carburetor Fuel Filter 35-53336Q\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/mercury-carburetor-fuel-filter-35-53336t\"\u003eMercury MerCruiser Carburetor Fuel Filter 35-53336T\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/mercury-mercruiser-quicksilver-fuel-filter-834011133\"\u003eMercury MerCruiser Quicksilver Fuel Filter 834011133\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/mercury-mercruiser-fuel-filter-8m0046752\"\u003eMercury MerCruiser Fuel Filter 8M0046752\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563862655012,"sku":"55278A1","price":11.79,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/e28b9860-f8f8-40bd-94db-d2d3f2d57759.png?v=1787267506","url":"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-diaphragm-kit-55278a1","provider":"Marisol Marine Company","version":"1.0","type":"link"}