{"product_id":"marine-switch-box-for-mercury-mercruiser-120hp-sport-jet-1995-1996-replaces-oem-826866a2-sierra-18-99305","title":"Sierra Switch Box 18-99305 for Mercury Mercruiser 4-Cylinder 120hp Sport Jet 1995-1996 - Replaces 826866A2","description":"\u003cp\u003eThe Sierra 18-99305 switch box is an ignition switch box built for 4-cylinder Mercury Mercruiser engines, specifically the 120hp Sport Jet model produced in 1995-1996. The switch box is a core component of the engine's ignition system, controlling spark timing and delivery to keep the engine firing correctly. Replacing a worn or failing switch box restores reliable starting and smooth running on engines where the original unit has degraded from age, vibration, or moisture exposure in the marine environment.\u003c\/p\u003e\u003cp\u003eThis switch box is a direct replacement for the OEM Mercury Mercruiser part 826866A2, so it installs in place of the original unit without modification to the ignition wiring or mounting points. It is intended for the 4-cylinder 120hp Sport Jet engine platform covered by that OEM number, making it a straightforward swap for owners maintaining or restoring this specific engine.\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 18-99305\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Ignition Switch Box\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine Application:\u003c\/strong\u003e Mercury Mercruiser 4-Cylinder 120hp Sport Jet\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModel Years:\u003c\/strong\u003e 1995-1996\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplaces (OEM):\u003c\/strong\u003e 826866A2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 1 pound\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282396091\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eMercury Mercruiser 4-Cylinder 120hp Sport Jet, 1995-1996\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e826866A2\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-99305 switch box fit?\u003c\/strong\u003e The Sierra 18-99305 is built for the Mercury Mercruiser 4-cylinder 120hp Sport Jet engine from 1995-1996.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-99305 switch box a direct replacement for the factory unit?\u003c\/strong\u003e Yes, the 18-99305 replaces OEM Mercury Mercruiser part number 826866A2 and installs in the same location without modifying the existing ignition wiring.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part number does the Sierra 18-99305 cross-reference?\u003c\/strong\u003e It replaces Mercury Mercruiser OEM number 826866A2.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the switch box weigh?\u003c\/strong\u003e The Sierra 18-99305 switch box weighs 1 pound.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat engine ignition system is this switch box part of?\u003c\/strong\u003e The 18-99305 is an ignition switch box that controls spark timing and delivery for the Mercury Mercruiser 4-cylinder 120hp Sport Jet engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this switch box work on other Mercury Mercruiser engines besides the 120hp Sport Jet?\u003c\/strong\u003e The Sierra 18-99305 is specified for the 4-cylinder 120hp Sport Jet engine, 1995-1996; fitment outside that application is not confirmed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat symptoms indicate the switch box needs to be replaced?\u003c\/strong\u003e Hard starting, misfiring, or a complete loss of spark on the 120hp Sport Jet engine are common signs the original switch box, replaced by the Sierra 18-99305, has failed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes installing the 18-99305 require rewiring the boat's ignition harness?\u003c\/strong\u003e No, the Sierra 18-99305 is a direct-fit replacement for OEM 826866A2 and uses the existing ignition wiring.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-99305 a genuine OEM part or an aftermarket equivalent?\u003c\/strong\u003e The 18-99305 is a Sierra-branded replacement part manufactured to replace OEM Mercury Mercruiser part 826866A2, not a Mercury-branded original part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the part number printed on this switch box?\u003c\/strong\u003e The part is identified by Sierra part number 18-99305.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988441542875,"sku":"SIE-18-99305","price":422.31,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/CDI-114-6866_lg__80929.1558110959.500.750.jpg?v=1785187997","url":"https:\/\/www.goodvibesmarina.com\/products\/marine-switch-box-for-mercury-mercruiser-120hp-sport-jet-1995-1996-replaces-oem-826866a2-sierra-18-99305","provider":"Good Vibes Marina","version":"1.0","type":"link"}