{"product_id":"sierra-18-5966-1-marine-alternator-55-amp-serpentine-pulley-replaces-oem-807652t-for-mercruiser-engines","title":"Sierra 55 Amp Alternator 18-5966-1 for MerCruiser GM V-8 Engines","description":"\u003cp\u003eThe Sierra 18-5966-1 is a 55 amp alternator built for MerCruiser GM V-8 sterndrive applications. It supplies reliable charging output to keep the starting battery and onboard electronics topped off during engine operation, replacing a worn or failed factory unit with a direct-fit part sized for the same engine bay.\u003c\/p\u003e\u003cp\u003eThe housing has a machined exterior finish for a clean, factory-correct appearance. At 8.25 x 6.13 x 6.13 inches and 11.34 pounds, it mounts using the factory bracket and pulley arrangement on the applicable MerCruiser GM V-8 engines listed below.\u003c\/p\u003e\u003cp\u003eThis alternator is cataloged against a range of MerCruiser GM V-8 engine and drive combinations, including 440 TRS, 454 Mag., 460 TRS, 465, 500 Bulldog, and 502 Mag. Bravo engines across their respective model years. Confirm your engine model and year against the fitment list before ordering.\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 18-5966-1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Alternator\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAmperage:\u003c\/strong\u003e 55 Amp\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExterior Finish:\u003c\/strong\u003e Machined\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Dimensions:\u003c\/strong\u003e 8.25 x 6.13 x 6.13 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 11.34 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282387068\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMerCruiser 440 TRS GM V-8, 1983-1986\u003c\/li\u003e\n\u003cli\u003eMerCruiser 454 Mag. GM V-8, 1986-1994\u003c\/li\u003e\n\u003cli\u003eMerCruiser 454 Mag. GM V-8, 1995-1997\u003c\/li\u003e\n\u003cli\u003eMerCruiser 460 TRS GM V-8, 1983-1986\u003c\/li\u003e\n\u003cli\u003eMerCruiser 465 GM V-8, 1990-1994\u003c\/li\u003e\n\u003cli\u003eMerCruiser 500 Bulldog GM V-8, 1990-1996\u003c\/li\u003e\n\u003cli\u003eMerCruiser 502 Mag. Bravo GM V-8, 1990-1993\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eNo OEM cross-reference numbers are listed for this part.\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat amperage does the Sierra 18-5966-1 alternator produce?\u003c\/strong\u003e This alternator is rated at 55 amps, sized to keep the starting battery and onboard electronics charged on applicable MerCruiser GM V-8 engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhich MerCruiser engines does the 18-5966-1 alternator fit?\u003c\/strong\u003e The 18-5966-1 is cataloged for MerCruiser GM V-8 440 TRS (1983-1986), 454 Mag. (1986-1994 and 1995-1997), 460 TRS (1983-1986), 465 (1990-1994), 500 Bulldog (1990-1996), and 502 Mag. Bravo (1990-1993) engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the dimensions of this alternator?\u003c\/strong\u003e The Sierra 18-5966-1 measures 8.25 x 6.13 x 6.13 inches.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-5966-1 alternator weigh?\u003c\/strong\u003e It weighs 11.34 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat finish does the alternator housing have?\u003c\/strong\u003e The housing on the 18-5966-1 has a machined exterior finish.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-5966-1 fit both 454 Mag. Model years?\u003c\/strong\u003e Yes, part number 18-5966-1 is listed for MerCruiser 454 Mag. GM V-8 engines across both the 1986-1994 and 1995-1997 model spans.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this a genuine Sierra part or aftermarket?\u003c\/strong\u003e The 18-5966-1 is a Sierra-branded alternator, sold under Sierra's own part number rather than an OEM engine manufacturer number.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill the 18-5966-1 work on a 500 Bulldog engine?\u003c\/strong\u003e Yes, it is cataloged for the MerCruiser 500 Bulldog GM V-8 engine for the 1990-1996 model years.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included when I order this alternator?\u003c\/strong\u003e The order includes one Sierra 18-5966-1 55 amp alternator unit.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes this alternator fit the 502 Mag. Bravo?\u003c\/strong\u003e Yes, the 18-5966-1 is listed for the MerCruiser 502 Mag. Bravo GM V-8 engine for the 1990-1993 model years.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the manufacturer part number for this alternator?\u003c\/strong\u003e The manufacturer part number is 18-5966-1, made by Sierra.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988347203803,"sku":"SIE-18-5966-1","price":233.64,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-5966-1__99076.1722368401.500.750.jpg?v=1785189073","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-5966-1-marine-alternator-55-amp-serpentine-pulley-replaces-oem-807652t-for-mercruiser-engines","provider":"Good Vibes Marina","version":"1.0","type":"link"}