{"product_id":"merc-66","title":"Mercury Quicksilver Screw 5\/16\"-24 × 1.12\" 20639","description":"\u003ch2\u003eMercury Quicksilver Screw 5\/16\"-24 × 1.12\" — Part 20639\u003c\/h2\u003e\n\u003cp\u003eA genuine Quicksilver OEM screw for Mercury and MerCruiser assemblies, catalogued as \u003cstrong\u003e10-20639\u003c\/strong\u003e. Thread size is \u003cstrong\u003e5\/16\"-24 (UNF fine thread) × 1.12\" length\u003c\/strong\u003e. This part has been discontinued and is no longer available through current Mercury production channels. No old-stock inventory is available — if you need this screw, a cross-reference to a standard 5\/16\"-24 UNF × 1-1\/8\" grade fastener with the correct finish and head style may be the only path forward.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eGenuine Quicksilver OEM fastener — original factory specification\u003c\/li\u003e\n\u003cli\u003ePart number: \u003cstrong\u003e20639\u003c\/strong\u003e \/ \u003cstrong\u003e10-20639\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eThread: \u003cstrong\u003e5\/16\"-24 UNF (fine thread) × 1.12\" length\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eDiscontinued — no longer in current Mercury production\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eFitment \u0026amp; Application\u003c\/h2\u003e\n\u003cp\u003eUse this screw where the Mercury or MerCruiser parts diagram specifies part number \u003cstrong\u003e20639\u003c\/strong\u003e or \u003cstrong\u003e10-20639\u003c\/strong\u003e. Fitment varies by engine model, drive type, and serial number range — always confirm against your specific parts diagram before ordering or substituting.\u003c\/p\u003e\n\n\u003ch2\u003eWhen to Replace\u003c\/h2\u003e\n\u003cp\u003eReplace when the screw is corroded, stripped, rounded, stretched, or has been removed from a critical assembly during service and cannot be safely reused. Fine-thread fasteners in particular should not be reused if there is any sign of thread damage or galling.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cp\u003eConfirm thread pitch (fine thread, 24 TPI), length, diameter, and finish against the diagram position before installation or substitution. Follow the Mercury service manual for torque specifications and locking compound requirements. If substituting with a standard fastener, match head style, drive type, and surface finish to the original.\u003c\/p\u003e\n\n\u003ch2\u003eRelated Products\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/marisolmarine.com\/products\/merc-85\"\u003eMercury Quicksilver Screw 5\/16\"-18 × 3\/4\" — 25299\u003c\/a\u003e — Coarse-thread 5\/16\"-18 UNC variant, limited old-stock available\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercruiser-screw-250-20-x-625-14070\"\u003eMercury MerCruiser Screw .250-20 × .625 — 14070\u003c\/a\u003e — 1\/4\"-20 UNC screw for Mercury \/ MerCruiser assemblies\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/marisolmarine.com\/products\/merc-97\"\u003eMercury MerCruiser Quicksilver Stainless Screw 28635\u003c\/a\u003e — Stainless OEM screw for corrosion-critical positions\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"https:\/\/marisolmarine.com\/products\/merc\"\u003eMercury MerCruiser Transom Plate Mounting Screw 8M0215010\u003c\/a\u003e — OEM transom plate mounting screw\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eBest use case:\u003c\/strong\u003e This listing is most useful as a reference when you need to identify the original OEM specification for the \u003cstrong\u003e10-20639\u003c\/strong\u003e position in a Mercury or MerCruiser parts diagram. Since the part is fully discontinued with no available stock, the practical next step is a cross-reference: a standard \u003cstrong\u003e5\/16\"-24 UNF × 1-1\/8\"\u003c\/strong\u003e cap screw or machine screw in the correct head style and finish will typically be the substitute. Confirm head style, drive type, and any coating or plating requirements from the service manual before substituting in a structural or sealing-critical position.\u003c\/p\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563840569380,"sku":"20639","price":1.2,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/8c6d1a1e-07c0-462f-bc74-30b93fe2b799.png?v=1786486542","url":"https:\/\/marisolmarine.com\/products\/merc-66","provider":"Marisol Marine Company","version":"1.0","type":"link"}