I bought a 94 merc that needed a switch box/power pack/brain. Anyway, I bought a used one and connected it properly using the manual, and when I pull it over, I get a spark, but not with each stroke, but after the end of the pull. I figure it's a grounding issue, because if your hand or foot is close or touching any part of the motor, you get the shock of your life. What am I doing wrong? Is my box bad? Or is it something under the flywheel? Or my wiring off?