I have an '87 Mercruiser 4.3L 175hp. I noticed yesterday when I was testing the engine before taking it out that when I start it up and rev the engine in neutral I hear sparks arching. Sounded like, tick tick tick tick tick tick. I looked back at the engine and noticed that there was a spark arching from under the center coil rubber boot to one of the terminals right next to it. <br /><br />This only happens when I rev the engine in neutral but when I rev it up in gear it doesn't do it. Why would it do this only in neutral. I understand that it shouldn't do it at all. The rubber boot of the center plug wire is pretty loose on the top of the ignition coil. Could this problem be resolved with a new center wire with a tighter fit or is there something else wrong? <br /><br />Any help would be greatly appreciated.