Johnson Evinrude Optical Sensor Tester 4/6 Cyl. CDI electronics WSM 511-4017 Used to test V4/V6 optical sensor on the engine or on the bench Unique design sounds an audible alert when setting the ignition timing, to allow an eyes free operation Replaces: 434017 OIS 2000 Sensor Tester Please check OEM#"s below for correct application of the item. At Pwc Engine,com we offer top name brands including WSM, Pro-X, Wiseco pistons, OEM RIK Japan rings, Nachi, Koyo, & KBC Engine bearings. PWC Engine use the highest quality gaskets and seals in the industry such as Athena USA, factory used ARS precision quality seals when available and much much more! If you are looking for performance parts, we offer the best distinguished brands and hand pick the parts that we know work and use daily.