{"product_id":"timer-base-for-johnson-evinrude-185-250-hp-v6-outboards-1988-2001-replaces-oem-584586-583533-763775","title":"Sierra 18-99391 Timer Base for Johnson Evinrude 6 Cylinder Outboards, 185-250 HP 1988-2001, Replaces 584586 583533 763775","description":"\u003cp\u003eThe Sierra 18-99391 timer base is a replacement ignition timing component for Johnson and Evinrude 6 cylinder loop charged outboard engines equipped with Quick Start and S.L.O.W. Systems. The timer base controls ignition timing advance as the throttle is opened, working in conjunction with the engine's ignition system to deliver correct spark timing across the RPM range. It uses a mechanical lift design to translate throttle linkage movement into timing advance.\u003c\/p\u003e\u003cp\u003eThis timer base is built for 6 cylinder Johnson\/Evinrude outboards rated 185, 200, 225, and 250 HP from 1988 through 2001 that use the loop charged, Quick Start, and S.L.O.W.-equipped ignition setup. It is a direct-fit replacement for the OEM timer base assembly and is intended to restore correct ignition timing operation on engines with a worn, cracked, or malfunctioning original unit. Installing a new timer base can resolve hard starting, rough idle, misfiring, or inconsistent timing advance caused by a failing original component.\u003c\/p\u003e\u003cp\u003eThe unit ships as a complete timer base assembly ready to install in place of the original equipment part, using the OEM mounting points and linkage connections. It weighs 0.9 pounds.\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 18-99391\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Ignition Timer Base\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Engine Configuration:\u003c\/strong\u003e 6 Cylinder, Loop Charged, Quick Start and S.L.O.W.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Horsepower:\u003c\/strong\u003e 185, 200, 225, 250 HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Years:\u003c\/strong\u003e 1988-2001\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLift Type:\u003c\/strong\u003e Mechanical\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.9 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Dimensions:\u003c\/strong\u003e 8 x 5 x 3 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282394240\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eJohnson\/Evinrude 6 cylinder loop charged engines with Quick Start and S.L.O.W., 185, 200, 225 and 250 HP, 1988-2001\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e584586\u003c\/li\u003e\n\u003cli\u003e583533\u003c\/li\u003e\n\u003cli\u003e763775\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-99391 timer base fit?\u003c\/strong\u003e It fits Johnson\/Evinrude 6 cylinder loop charged outboard engines with Quick Start and S.L.O.W. Rated at 185, 200, 225, and 250 HP, built between 1988 and 2001.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part numbers does this timer base replace?\u003c\/strong\u003e The Sierra 18-99391 timer base replaces OEM numbers 584586, 583533, and 763775.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-99391 timer base weigh?\u003c\/strong\u003e It weighs 0.9 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the dimensions of the timer base?\u003c\/strong\u003e The Sierra 18-99391 timer base measures 8 x 5 x 3 inches.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the timer base a mechanical or electronic unit?\u003c\/strong\u003e It uses a mechanical lift design to advance ignition timing as the throttle is opened.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes this timer base work with S.L.O.W.-equipped engines?\u003c\/strong\u003e Yes, the 18-99391 is designed for 6 cylinder Johnson\/Evinrude engines equipped with both Quick Start and S.L.O.W. Systems.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this fit a 200 HP Evinrude from 1995?\u003c\/strong\u003e Yes, provided it is a 6 cylinder loop charged model with Quick Start and S.L.O.W., the 18-99391 timer base covers 185-250 HP engines built 1988-2001, which includes that engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat symptoms indicate the timer base needs replacement?\u003c\/strong\u003e Hard starting, rough idle, misfiring, or inconsistent ignition timing advance on a covered Johnson\/Evinrude 6 cylinder engine can indicate a worn or failing timer base like the 18-99391 needs replacement.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I cross-reference this part using my old OEM number?\u003c\/strong\u003e Yes, if your old timer base is stamped 584586, 583533, or 763775, the Sierra 18-99391 is the correct replacement.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes installing the 18-99391 require any modification to the engine?\u003c\/strong\u003e No, it is a direct-fit replacement that installs at the OEM mounting points and linkage connections without modification.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs this the complete timer base assembly?\u003c\/strong\u003e Yes, the Sierra 18-99391 ships as a complete, ready-to-install timer base assembly.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988442460379,"sku":"SIE-18-99391","price":466.19,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/CDI-133-3533_lg__14594.1722367210.500.750.jpg?v=1785188155","url":"https:\/\/www.goodvibesmarina.com\/products\/timer-base-for-johnson-evinrude-185-250-hp-v6-outboards-1988-2001-replaces-oem-584586-583533-763775","provider":"Good Vibes Marina","version":"1.0","type":"link"}