{"product_id":"sierra-18-99547-marine-spark-tester-for-4-cylinder-outboards-ignition-spark-checker-tool","title":"Sierra Spark Tester for 4 Cylinder Mercury Outboards, Part 18-99547","description":"\u003cp\u003eThe Sierra Spark Tester, part number 18-99547, is an in-line spark checker built for diagnosing ignition problems on 4 cylinder Mercury outboard engines. Instead of pulling a spark plug and guessing at spark quality by eye, this tester lets you check for consistent, visible spark directly in line with the plug wire while the engine is cranking or running, which makes it much easier to isolate a weak coil, bad plug wire, or faulty ignition component before you start swapping parts. It is built with a copper core for reliable conductivity during repeated testing.\u003c\/p\u003e\u003cp\u003eThis is a diagnostic tool sized specifically for 4 cylinder outboard applications, so it is set up to test spark across all four cylinders of a compatible Mercury outboard engine. It is a straightforward addition to any marine mechanic's or DIY boater's toolbox for troubleshooting no-start conditions, rough idle, or misfire complaints tied to the ignition system.\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 18-99547\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Name:\u003c\/strong\u003e Spark Tester - 4 Cyl.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCategory:\u003c\/strong\u003e Mercury Outboard Specialty Tools\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder Configuration:\u003c\/strong\u003e 4 Cylinder\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCore Material:\u003c\/strong\u003e Copper\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.8 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282395247\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e4 cylinder Mercury outboard engines\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat does the Sierra 18-99547 spark tester do?\u003c\/strong\u003e It checks for spark on 4 cylinder Mercury outboard engines by connecting in line with the spark plug wire, letting you visually confirm consistent spark while the engine cranks or runs instead of pulling the plug to guess.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many cylinders does this spark tester cover?\u003c\/strong\u003e The 18-99547 tester is built for 4 cylinder outboard engines, matching the ignition layout of a 4 cylinder Mercury outboard.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-99547 only for Mercury outboards?\u003c\/strong\u003e It is categorized and sized for 4 cylinder Mercury outboard engines, so that is its intended application.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the spark tester's contact core made of?\u003c\/strong\u003e The core of part 18-99547 is copper, chosen for reliable electrical conductivity during repeated spark checks.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-99547 spark tester weigh?\u003c\/strong\u003e It weighs 0.8 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan this tool diagnose a no-start condition?\u003c\/strong\u003e Yes, checking for spark with the 18-99547 is a standard first step in diagnosing a no-start or misfire, since it isolates whether the ignition system is delivering spark to the cylinder.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need to remove the spark plug to use this tester?\u003c\/strong\u003e No, the 18-99547 connects in line with the plug wire so you can check spark without pulling the spark plug.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-99547 a genuine Sierra part?\u003c\/strong\u003e Yes, 18-99547 is the Sierra manufacturer part number for this spark tester.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat ignition problems can this tester help identify?\u003c\/strong\u003e Weak or missing spark, a failing ignition coil, or a bad plug wire on a 4 cylinder Mercury outboard can all be narrowed down using the 18-99547 spark tester.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included with part 18-99547?\u003c\/strong\u003e The product is the Sierra spark tester itself, part number 18-99547, sized for 4 cylinder outboard ignition testing.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988446261467,"sku":"SIE-18-99547","price":117.91,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/CDI-519-S48H_lg__88665.1558113209.500.750.jpg?v=1785188258","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-99547-marine-spark-tester-for-4-cylinder-outboards-ignition-spark-checker-tool","provider":"Good Vibes Marina","version":"1.0","type":"link"}