I recently purchased a boat with a 80's Mercury 50 2 stroke 4 cy motor. I took it out and couldn't keep up with a 10HP. After looking more into it, i found that I have no spark on #2 spark plug. After pulling a wiring diagram and checking I saw that the wiring didn't match what the switch box says and the wiring diagram. Where the box and diagram show to be a green wire from coil #1 is connected to where they show the green/red should be. To make a long story short, my green and green/red wires are reversed from what the switch box is calling for along with the diagram. When I swapped them to match the switch box and diagram say, it won't start. Does anyone have a clue what the heck is going on. The motor runs fine with muffs, but it is terrible in the water.