{"product_id":"sierra-18-5817d-starter-solenoid-for-mercruiser-mercury","title":"Sierra 18-5817D Starter Solenoid for Mercruiser\/Mercury","description":"\u003cp class=\"nvn-hero\"\u003eThe Sierra 18-5817D is a direct-fit starter solenoid for Mercruiser stern drives and Mercury outboards. When your engine clicks but won't crank, this is the part that hands full battery current to the starter. It drops in with a vertical post design, a built-in stepped mounting plate, and an angled bracket, so it bolts up just like the original.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eTurn the key on your Mercruiser stern drive or Mercury outboard and you expect the starter to spin right up. When it doesn't, when you get a single click or dead silence, the starter solenoid is one of the first parts a good mechanic checks. The Sierra 18-5817D is a direct-fit replacement for that solenoid, built to drop onto the same engines that ran the factory unit.\u003c\/p\u003e\n\u003cp\u003eSo what does a solenoid actually do? It's the heavy-duty relay that sits between your ignition switch and the starter motor. The wire from your key switch can't carry the huge current a starter pulls. Instead, it sends a small trigger current to the solenoid's coil. That coil pulls a set of contacts closed, and those contacts hand full battery power straight to the starter. Small signal in, big current out. That's the whole job, and it's a job that has to work every single time you want to leave the dock.\u003c\/p\u003e\n\u003cp\u003eOut on the water, solenoids live a hard life. Salt air, humidity, engine heat, and constant vibration all gang up on the contacts and the coil inside. Over the years the contacts pit and burn, the coil weakens, and one morning the engine just won't turn over. It's one of the most common no-crank causes on older Mercruiser and Mercury rigs, and it's easy to overlook because it fails quietly. No warning, no noise. Just a click.\u003c\/p\u003e\n\u003cp\u003eThis is where the Sierra replacement earns its keep. Sierra engineers their parts to meet or exceed the original equipment they replace, and this one is built to stand up in the harsh marine environment. It uses a vertical post design, so the terminals sit where you expect them. It has a built-in stepped mounting plate and an angled bracket, which means it bolts up to the factory location without you fabricating a new mount or drilling fresh holes. If you've ever fought a replacement part that almost fit, you'll appreciate that.\u003c\/p\u003e\n\u003cp\u003eFitment is the thing to get right, so check your numbers before you order. This unit replaces Mercruiser stern drive part numbers 89-94318, 89-846070, 89-96158, and 89-96158T, along with Mercury Marine outboard numbers 89-96158 and 89-96158T. Pull your old solenoid, read the number stamped or printed on the body, and match it to that list. If it lines up, this is your part.\u003c\/p\u003e\n\u003cp\u003eInstalling it yourself is well within reach for most owners. Start by disconnecting the battery. Then snap a photo of the wiring before you touch anything, because getting the trigger wire and the heavy cables back on the right posts matters. Transfer the connections one at a time from the old solenoid to the new one, snug everything down, reconnect the battery, and turn the key. While you're in there, give the terminals and cable ends a quick wire-brush cleaning, because a corroded connection can mimic a bad solenoid and send you chasing the wrong problem. When it cranks strong again, you're done. No special tools, no dealer trip.\u003c\/p\u003e\n\u003cp\u003eWho's this for? Anyone keeping an older Mercruiser or Mercury engine running, whether that's a weekend runabout, a cabin cruiser, or a repower project on the bench. It's also smart to keep a spare aboard if you run offshore, since a dead solenoid a few miles out is a bad day you can prevent by tossing a spare in your kit.\u003c\/p\u003e\n\u003cp\u003eOne note on what you're getting. This is the solenoid in a retail display pack. It's the replacement relay itself with its integral mounting plate and bracket, not a full wiring or hardware kit, so reuse your existing cables and fasteners unless they're corroded past saving. Match the number, bolt it in, and get back on the water.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eDirect-fit replacement starter solenoid for Mercruiser stern drive and Mercury outboard engines\u003c\/li\u003e\n  \u003cli\u003eVertical post terminal design keeps the connections in the factory layout\u003c\/li\u003e\n  \u003cli\u003eBuilt-in stepped mounting plate bolts up to the original location with no fabrication\u003c\/li\u003e\n  \u003cli\u003eAngled bracket positions the solenoid to factory geometry for a clean fit\u003c\/li\u003e\n  \u003cli\u003eReplaces Mercruiser 89-94318, 89-846070, 89-96158, 89-96158T and Mercury Marine 89-96158, 89-96158T\u003c\/li\u003e\n  \u003cli\u003eEngineered by Sierra to meet or exceed the OEM part it replaces\u003c\/li\u003e\n  \u003cli\u003eBuilt to stand up to salt, humidity, heat, and vibration in the marine environment\u003c\/li\u003e\n  \u003cli\u003eShips in a retail display pack\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Sierra Marine reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat engines does the Sierra 18-5817D fit?\u003c\/summary\u003e\n    \u003cp\u003eIt's a direct-fit starter solenoid for Mercruiser stern drives and Mercury outboards. It replaces Mercruiser numbers 89-94318, 89-846070, 89-96158, and 89-96158T, plus Mercury Marine numbers 89-96158 and 89-96158T. Match your old part number to that list before ordering.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat does a starter solenoid actually do?\u003c\/summary\u003e\n    \u003cp\u003eIt's the heavy-duty relay between your ignition switch and the starter motor. The key switch sends a small trigger current to the solenoid coil, the coil closes a set of contacts, and those contacts pass full battery current to the starter so the engine can crank.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I know my solenoid has failed?\u003c\/summary\u003e\n    \u003cp\u003eThe classic sign is a single click, or dead silence, when you turn the key while the battery is charged. Contacts pit and burn and the coil weakens over time, so a no-crank with good battery voltage often points straight at the solenoid.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes it come with mounting hardware?\u003c\/summary\u003e\n    \u003cp\u003eIt has a built-in stepped mounting plate and an angled bracket, so it bolts up to the factory location. It ships as the solenoid in a display pack, not a full wiring or hardware kit, so plan to reuse your existing cables and fasteners.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this a genuine OEM part?\u003c\/summary\u003e\n    \u003cp\u003eIt's a Sierra replacement, engineered to meet or exceed the original equipment it replaces. Sierra builds it for the marine environment and lists the OEM Mercruiser and Mercury numbers it's designed to replace.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat OEM part numbers does it replace?\u003c\/summary\u003e\n    \u003cp\u003eOn Mercruiser stern drives it replaces 89-94318, 89-846070, 89-96158, and 89-96158T. On Mercury Marine outboards it replaces 89-96158 and 89-96158T.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill it hold up to salt water and vibration?\u003c\/summary\u003e\n    \u003cp\u003eIt's engineered for the harsh marine environment, where salt air, humidity, heat, and constant vibration wear out lesser parts. Sierra builds their replacements to meet or exceed the original equipment on that front.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan I install it myself?\u003c\/summary\u003e\n    \u003cp\u003eYes, it's a straightforward job for most owners. Disconnect the battery, photograph the wiring, transfer the connections one at a time from the old solenoid to the new one, snug everything down, reconnect the battery, and test. No special tools needed.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat comes in the display pack?\u003c\/summary\u003e\n    \u003cp\u003eYou get the replacement solenoid with its integral stepped mounting plate and angled bracket in retail display packaging. It does not include replacement cables or fasteners.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eSierra 18-5817D Marine Starter Solenoid\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eSierra Marine\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e18-5817D\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e808282184919\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eComponent Type\u003c\/th\u003e\n\u003ctd\u003eStarter Solenoid\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFits Engines\u003c\/th\u003e\n\u003ctd\u003eMercruiser Stern Drive, Mercury Marine Outboard\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePost Type\u003c\/th\u003e\n\u003ctd\u003eVertical Post\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eMounting Plate\u003c\/th\u003e\n\u003ctd\u003eBuilt-In Stepped Mounting Plate\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBracket\u003c\/th\u003e\n\u003ctd\u003eAngled Bracket\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePackaging\u003c\/th\u003e\n\u003ctd\u003eDisplay Pack\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eReplaces (Mercruiser Stern Drive)\u003c\/th\u003e\n\u003ctd\u003e89-94318, 89-846070, 89-96158, 89-96158T\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eReplaces (Mercury Marine)\u003c\/th\u003e\n\u003ctd\u003e89-96158, 89-96158T\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What engines does the Sierra 18-5817D fit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's a direct-fit starter solenoid for Mercruiser stern drives and Mercury outboards. It replaces Mercruiser numbers 89-94318, 89-846070, 89-96158, and 89-96158T, plus Mercury Marine numbers 89-96158 and 89-96158T. Match your old part number to that list before ordering.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What does a starter solenoid actually do?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's the heavy-duty relay between your ignition switch and the starter motor. The key switch sends a small trigger current to the solenoid coil, the coil closes a set of contacts, and those contacts pass full battery current to the starter so the engine can crank.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How do I know my solenoid has failed?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The classic sign is a single click, or dead silence, when you turn the key while the battery is charged. Contacts pit and burn and the coil weakens over time, so a no-crank with good battery voltage often points straight at the solenoid.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does it come with mounting hardware?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It has a built-in stepped mounting plate and an angled bracket, so it bolts up to the factory location. It ships as the solenoid in a display pack, not a full wiring or hardware kit, so plan to reuse your existing cables and fasteners.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is this a genuine OEM part?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's a Sierra replacement, engineered to meet or exceed the original equipment it replaces. Sierra builds it for the marine environment and lists the OEM Mercruiser and Mercury numbers it's designed to replace.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What OEM part numbers does it replace?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"On Mercruiser stern drives it replaces 89-94318, 89-846070, 89-96158, and 89-96158T. On Mercury Marine outboards it replaces 89-96158 and 89-96158T.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Will it hold up to salt water and vibration?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's engineered for the harsh marine environment, where salt air, humidity, heat, and constant vibration wear out lesser parts. Sierra builds their replacements to meet or exceed the original equipment on that front.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Can I install it myself?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes, it's a straightforward job for most owners. Disconnect the battery, photograph the wiring, transfer the connections one at a time from the old solenoid to the new one, snug everything down, reconnect the battery, and test. No special tools needed.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What comes in the display pack?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"You get the replacement solenoid with its integral stepped mounting plate and angled bracket in retail display packaging. It does not include replacement cables or fasteners.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Sierra Marine","offers":[{"title":"Default Title","offer_id":45078005416029,"sku":"2009840","price":24.59,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_dcb77e2e-2775-4a8e-8756-580ef33705a9.jpg?v=1789925835","url":"https:\/\/nvnmarine.com\/products\/sierra-18-5817d-starter-solenoid-for-mercruiser-mercury","provider":"NVN Marine","version":"1.0","type":"link"}