{"product_id":"sierra-18-99565-internal-engine-wiring-harness-for-johnson-evinrude-outboards-round-plug-connector","title":"Sierra Johnson\/Evinrude Round Plug Internal Engine Wiring Harness 18-99565","description":"\u003cp\u003eThe Sierra 18-99565 is an internal engine wiring harness built for Johnson\/Evinrude outboards that use a round plug connection. It carries the engine's electrical circuits between the powerhead components and the main wiring connector, providing a direct replacement path when an original harness has become corroded, cracked, or damaged from heat and vibration over time. The harness uses copper conductors for reliable electrical conductivity and is terminated with a DIN-style connector to mate with the round plug interface found on compatible Johnson\/Evinrude engines.\u003c\/p\u003e\u003cp\u003eCopper wiring resists corrosion better than lower-grade alloys and helps maintain consistent voltage delivery to ignition and charging components, which is critical for dependable starting and running on the water. Because this harness routes internally through the engine, it is intended for outboards originally equipped with a round plug wiring configuration rather than the later rectangular multi-pin connector style. Boat owners and marine technicians use this harness during engine rebuilds, electrical troubleshooting, or as a preventive replacement when a harness shows visible wear.\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 18-99565\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Evinrude Outboard Electrical System\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConnector Type:\u003c\/strong\u003e DIN (round plug)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Copper\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.7 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eJohnson\/Evinrude outboard engines with round plug internal wiring configuration\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-99565 wiring harness fit?\u003c\/strong\u003e The Sierra 18-99565 is built for Johnson\/Evinrude outboard engines that use a round plug internal wiring configuration.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat connector type does this harness use?\u003c\/strong\u003e It terminates in a DIN-style round plug connector, matching the internal wiring interface on compatible Johnson\/Evinrude engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-99565 harness weigh?\u003c\/strong\u003e This harness weighs 0.7 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material are the wires made of?\u003c\/strong\u003e The Sierra 18-99565 harness uses copper conductors for reliable electrical conductivity.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this a genuine Sierra part?\u003c\/strong\u003e Yes, 18-99565 is the Sierra manufacturer part number for this internal engine wiring harness.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhen would I need to replace this harness?\u003c\/strong\u003e Replacement is typically needed when the original engine harness shows corrosion, cracking, or heat and vibration damage that causes electrical faults or hard starting.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes this harness fit outboards with a rectangular multi-pin connector?\u003c\/strong\u003e No, the 18-99565 is designed for the round plug internal wiring configuration, not the rectangular multi-pin style.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs installation something a boat owner can do, or does it require a technician?\u003c\/strong\u003e Because the 18-99565 routes internally through the engine, installation typically involves engine teardown and is commonly performed by a marine technician or an experienced DIY mechanic during a rebuild.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat electrical systems does this harness connect?\u003c\/strong\u003e The Sierra 18-99565 carries the engine's ignition and charging circuits between the powerhead components and the main engine wiring connector.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy choose copper wiring over other materials?\u003c\/strong\u003e Copper resists corrosion and maintains consistent voltage delivery better than lower-grade wire alloys, which supports dependable starting and running.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988446851291,"sku":"SIE-18-99565","price":155.37,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/CDI-413-3771_lg__55422.1558113554.500.750.jpg?v=1785188951","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-99565-internal-engine-wiring-harness-for-johnson-evinrude-outboards-round-plug-connector","provider":"Good Vibes Marina","version":"1.0","type":"link"}