{"product_id":"sierra-18-0320-reed-block-gasket-for-mercury-outboards-replaces-mercury-27-13937-27-139374","title":"Sierra 18-0320 Reed Block Gasket - Cross Reference Mercury 27-13937","description":"\u003cp\u003eThe Sierra 18-0320 is a reed block gasket built for outboard engine service, sealing the mating surface between the reed valve block and the powerhead to maintain proper crankcase compression and prevent air or fuel leaks at the joint. It is manufactured from a glass-based gasket material designed to hold a consistent seal under the heat cycling and vibration typical of outboard operation. Each Sierra gasket is engineered to meet or exceed the quality of the original equipment part it replaces, making it a straightforward direct-fit replacement during a reed block rebuild, powerhead service, or routine maintenance. The 18-0320 is a single-piece gasket supplied as one unit, sized to match the reed block gasket used across a range of Mercury outboard applications that call for this specific part. Because it corresponds to several historical OEM and aftermarket part numbers, it is commonly sourced as a replacement whenever an older reference number is found stamped on the block or listed in a parts diagram. Installers should confirm the old gasket's dimensions and bolt pattern against the 18-0320 before ordering, and always install a new gasket rather than reusing the old one to ensure a proper seal.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-0320\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eItem Type:\u003c\/strong\u003e Reed Block Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Glass\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e Multi-coloured\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnit Count:\u003c\/strong\u003e 1 gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.02 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999873101\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross-Reference:\u003c\/strong\u003e GLM 32220, Mallory 9-60061, Mercury 27-13937-6, 27-139374, 27-139372, 27-13937\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eGLM 32220\u003c\/li\u003e\n\u003cli\u003eMallory 9-60061\u003c\/li\u003e\n\u003cli\u003eMercury 27-13937-6\u003c\/li\u003e\n\u003cli\u003eMercury 27-139374\u003c\/li\u003e\n\u003cli\u003eMercury 27-139372\u003c\/li\u003e\n\u003cli\u003eMercury 27-13937\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat is the Sierra 18-0320 used for?\u003c\/strong\u003e The Sierra 18-0320 is a reed block gasket that seals the joint between the reed valve block and the powerhead on applicable outboard engines, maintaining proper crankcase sealing.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-0320 gasket the same as Mercury 27-13937?\u003c\/strong\u003e Yes, the Sierra 18-0320 Reed Block Gasket is a direct cross-reference for Mercury 27-13937, 27-13937-6, 27-139374, and 27-139372, along with GLM 32220 and Mallory 9-60061.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is the 18-0320 reed block gasket made from?\u003c\/strong\u003e It is made from a glass-based gasket material designed to hold a consistent seal under engine heat and vibration.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many gaskets are included with part number 18-0320?\u003c\/strong\u003e One reed block gasket is included per unit count for the Sierra 18-0320.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-0320 gasket weigh?\u003c\/strong\u003e It weighs 0.02 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the Sierra 18-0320 meet original equipment quality?\u003c\/strong\u003e Sierra states this gasket meets or exceeds the quality of the original equipment part it replaces, making the 18-0320 a reliable equivalent to OEM.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I reuse my old reed block gasket instead of installing the 18-0320?\u003c\/strong\u003e No, a gasket should not be reused once removed; installing a new Sierra 18-0320 ensures a proper seal at the reed block joint.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the 18-0320 gasket?\u003c\/strong\u003e The gasket has a multi-coloured appearance, consistent with its glass-based gasket material.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-0320 an aftermarket or genuine Mercury part?\u003c\/strong\u003e The 18-0320 is a Sierra-brand aftermarket gasket engineered as a cross-reference equivalent to the Mercury 27-13937 series parts, not a Mercury-branded part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the UPC for the Sierra 18-0320 reed block gasket?\u003c\/strong\u003e The UPC is 030999873101.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988062777563,"sku":"SIE-18-0320","price":3.46,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-0320_lg__55148.1637358372.500.750.jpg?v=1785188626","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-0320-reed-block-gasket-for-mercury-outboards-replaces-mercury-27-13937-27-139374","provider":"Good Vibes Marina","version":"1.0","type":"link"}