Re: running great shut down no spark merc 402
The orange/salmon wire grounds the ignition system(the switchbox) out and "kills the motor". Test by disconnecting the salmon/orange wire that goes to the switchbox from the "junction block" and try starting. At the junction block one of the wires connected to it goes to the tilt safety/mercury switch and the other goes forward through the loom to the ignition switch. If the engine runs with the salmon wire diconnected then you probably have a bad mercury switch or a short somewhere in the other wire that goes to the ignition swich or...your ignition switch could be bad. I had the same problem/symptoms and it turned out that the switch wire was shorting in two spots. I replaced the whole length of the wire and problem was solved.