i just recently bought a 1990 lowe pontoon boat with a 90hp evinrude, the carbs were just rebuilt, all the coil packs are new, plug wires are new and for some reason im getting no visible spark from the top right cylinder. its a v4 engine. sometimes when you take off the plug wire and put it back on it sounds different in the motor like its not getting spark but i cant see any spark and sometimes it makes no real different sound. what could be some of my problems? what else would give it no spark? Thank you very much in advance:!! 