{"product_id":"sierra-18-99392-marine-wiring-harness-for-mercury-mariner-outboards-20-150-hp-2-4-6-cylinder-1966-1981","title":"Sierra 18-99392 Mercury\/Mariner Outboard Wiring Harness, 2\/4\/6 Cylinder Engines 1966-1981","description":"\u003cp\u003eThe Sierra 18-99392 is a wiring harness built to connect Mercury and Mariner outboard engines to the boat's control and instrument wiring. It carries copper conductors terminated with a Mercury\/Mariner engine wiring connector, giving a direct plug-in fit at the engine end so the harness routes power and signal wiring between the outboard and the helm without splicing into factory connectors. This harness is sized for a range of Mercury\/Mariner outboards spanning 2, 4, and 6 cylinder configurations built between 1966 and 1981, covering horsepower ratings from 20 HP up through 150 HP depending on cylinder count and model year. Copper wiring resists corrosion better than lower-grade conductors and is a standard choice for marine electrical applications exposed to moisture and vibration. Because outboard wiring connectors and pin configurations vary by model year and horsepower, buyers should confirm the harness connector matches their engine's original wiring connector before ordering, or check the manufacturer's recommended part number for their specific application. This harness is intended as a replacement or repair harness where the factory wiring has degraded, corroded, or been damaged, restoring a clean connection between the outboard and the boat's electrical system.\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 18-99392\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Mercury Outboard Electrical System\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Copper\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnector Type:\u003c\/strong\u003e Mercury\/Mariner Engine Wiring Connector\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eItem Dimensions:\u003c\/strong\u003e 7 x 9 x 2.5 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 1.2 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Engines:\u003c\/strong\u003e 20 and 40 HP (2 cylinder), 50, 65, 80 and 85 HP (4 cylinder), 90, 95, 100, 115, 125, 135, 140 and 150 HP (6 cylinder)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Years:\u003c\/strong\u003e 1966-1981\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282394257\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMercury\/Mariner 20 and 40 HP, 2 cylinder outboards, 1970-1981\u003c\/li\u003e\n\u003cli\u003eMercury\/Mariner 50, 65, 80 and 85 HP, 4 cylinder outboards, 1967-1975\u003c\/li\u003e\n\u003cli\u003eMercury\/Mariner 90, 95, 100, 115, 125, 135, 140 and 150 HP, 6 cylinder outboards, 1966-1979\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-99392 wiring harness fit?\u003c\/strong\u003e The Sierra 18-99392 fits Mercury\/Mariner 2, 4, and 6 cylinder outboards, covering 20 and 40 HP (2 cylinder) models from 1970-1981, 50, 65, 80 and 85 HP (4 cylinder) models from 1967-1975, and 90, 95, 100, 115, 125, 135, 140 and 150 HP (6 cylinder) models from 1966-1979.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this harness made with copper wiring?\u003c\/strong\u003e Yes, the Sierra 18-99392 wiring harness uses copper conductors, which hold up well against the corrosion and vibration common in marine electrical systems.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the dimensions of the 18-99392 harness?\u003c\/strong\u003e The Sierra 18-99392 measures 7 x 9 x 2.5 inches as packaged.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-99392 wiring harness weigh?\u003c\/strong\u003e It weighs 1.2 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-99392 harness use the original Mercury connector?\u003c\/strong\u003e Yes, the Sierra 18-99392 terminates in a Mercury\/Mariner engine wiring connector designed to plug into the factory connection point on compatible outboards.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this harness work on any Mercury outboard?\u003c\/strong\u003e No, the Sierra 18-99392 is designed for specific Mercury\/Mariner horsepower and cylinder configurations built between 1966 and 1981, so buyers should confirm their engine's horsepower, cylinder count, and model year fall within the listed ranges before ordering.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy would I need to replace my outboard's wiring harness?\u003c\/strong\u003e A wiring harness like the Sierra 18-99392 is typically replaced when the original harness has corroded, frayed, or been damaged, causing intermittent electrical connections or engine control issues.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-99392 a direct plug-in replacement?\u003c\/strong\u003e Yes, its Mercury\/Mariner engine wiring connector is built to connect at the same point as the factory harness on compatible engines, so no splicing into the original wiring is required at the connector.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when I order the 18-99392 harness?\u003c\/strong\u003e The Sierra 18-99392 order includes the complete wiring harness with its Mercury\/Mariner engine wiring connector attached.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use this harness on a 6 cylinder Mercury outboard?\u003c\/strong\u003e Yes, the Sierra 18-99392 covers 6 cylinder Mercury\/Mariner outboards rated 90, 95, 100, 115, 125, 135, 140 and 150 HP from 1966-1979.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes horsepower affect which harness connector I need?\u003c\/strong\u003e Yes, connector configuration on Mercury\/Mariner outboards varies by horsepower and model year, so it is important to check the manufacturer's recommended part number for your specific engine before installing the 18-99392.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988442656987,"sku":"SIE-18-99392","price":225.55,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/CDI-414-2770_lg__61837.1722478587.500.750.jpg?v=1785189072","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-99392-marine-wiring-harness-for-mercury-mariner-outboards-20-150-hp-2-4-6-cylinder-1966-1981","provider":"Good Vibes Marina","version":"1.0","type":"link"}