{"product_id":"johnson-evinrude-timer-base-6-cyl-ignition-replaces-oem-583376-sierra-18-99423-fits-1979-1988-cross-flow-150-235-hp","title":"Sierra Timer Base 18-99423 for Johnson Evinrude 6 Cylinder Cross Flow Engines 1979-1988","description":"\u003cp\u003eThe Sierra 18-99423 Timer Base is an ignition component designed for Johnson\/Evinrude 6 cylinder Cross Flow outboard engines equipped with twin power packs. The timer base works with the ignition system to regulate spark timing across the engine's cylinders, and is a common wear-and-replace item when an outboard develops rough running, misfires, or inconsistent timing at various RPM ranges. Replacing a worn or failing timer base restores accurate ignition timing and helps the engine return to smooth, reliable operation.\u003c\/p\u003e\u003cp\u003eThis timer base is built to fit the Johnson\/Evinrude 6 cylinder Cross Flow engine family covering the 1979-1988 model years, across the 150, 155, 175, 185, 200, and 235 HP outboard variants that use twin power packs. It is intended as a direct fit for these applications and is cross-referenced to several factory OEM part numbers, making it easy to identify as the correct replacement when servicing these engines.\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 18-99423\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Timer Base\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Engine Family:\u003c\/strong\u003e Johnson\/Evinrude 6 Cylinder Cross Flow\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Horsepower:\u003c\/strong\u003e 150, 155, 175, 185, 200, 235 HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCompatible Model Years:\u003c\/strong\u003e 1979-1988\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePower Pack Configuration:\u003c\/strong\u003e Twin power pack\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.8 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Dimensions:\u003c\/strong\u003e 7 x 5 x 3 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282394547\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eJohnson\/Evinrude 6 cylinder Cross Flow engines with twin power packs: 150, 155, 175, 185, 200, and 235 HP, 1979-1988\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e763783\u003c\/li\u003e\n\u003cli\u003e583376\u003c\/li\u003e\n\u003cli\u003e582041\u003c\/li\u003e\n\u003cli\u003e581812\u003c\/li\u003e\n\u003cli\u003e583127\u003c\/li\u003e\n\u003cli\u003e583128\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-99423 timer base fit?\u003c\/strong\u003e It fits Johnson\/Evinrude 6 cylinder Cross Flow outboard engines with twin power packs, covering the 150, 155, 175, 185, 200, and 235 HP models from 1979-1988.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes part 18-99423 work with single power pack ignition systems?\u003c\/strong\u003e No, the Sierra 18-99423 timer base is designed for the twin power pack configuration used on 1979-1988 Johnson\/Evinrude 6 cylinder Cross Flow engines, not single power pack setups.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part numbers does 18-99423 replace?\u003c\/strong\u003e This timer base cross-references to OEM numbers 763783, 583376, 582041, 581812, 583127, and 583128.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the timer base weigh?\u003c\/strong\u003e The Sierra 18-99423 timer base weighs 0.8 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat are the dimensions of this timer base?\u003c\/strong\u003e It measures 7 x 5 x 3 inches.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat symptoms indicate a timer base needs to be replaced?\u003c\/strong\u003e Rough running, misfires, or inconsistent ignition timing across RPM ranges on a Johnson\/Evinrude 6 cylinder Cross Flow engine are common signs that the timer base, such as Sierra 18-99423, needs replacement.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-99423 a genuine Sierra part?\u003c\/strong\u003e Yes, 18-99423 is a Sierra-brand ignition timer base, sold under Sierra's own part number.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill this timer base fit engines outside the 1979-1988 range?\u003c\/strong\u003e The Sierra 18-99423 is specified for the 1979-1988 Johnson\/Evinrude 6 cylinder Cross Flow engine range with twin power packs; fitment outside those years is not confirmed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the timer base come with mounting hardware?\u003c\/strong\u003e The listing covers the Sierra 18-99423 timer base component itself; no additional included hardware is specified.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use the UPC to verify I'm ordering the correct timer base?\u003c\/strong\u003e Yes, the Sierra 18-99423 timer base carries UPC 808282394547, which can be used to confirm the correct product when ordering.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat horsepower ratings use this timer base?\u003c\/strong\u003e The 150, 155, 175, 185, 200, and 235 HP Johnson\/Evinrude 6 cylinder Cross Flow engines with twin power packs use the 18-99423 timer base.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988443410651,"sku":"SIE-18-99423","price":346.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/CDI-133-3377__53310.1737852737.500.750.jpg?v=1785188640","url":"https:\/\/www.goodvibesmarina.com\/products\/johnson-evinrude-timer-base-6-cyl-ignition-replaces-oem-583376-sierra-18-99423-fits-1979-1988-cross-flow-150-235-hp","provider":"Good Vibes Marina","version":"1.0","type":"link"}