Those kill switches are fairly basic, there is usually three wires, two cream colored ones and a black ground inside a shrink wrapped harness. These cream colored wires match up to the ones from the stator, one to each set of contact points. The button has a disc in it that connects the two cream wires together. The ground wire is there to add a ground path from the cowl to the block. The wires used had very poor insulation and it is very common for them to have lost their insulation. Check to see if they have shorted together in the loom, either to each other or to the ground wire. Either way, it will cause a miss or completely dead motor. Not long ago, I purchased a NOS kill switch assembly for one of my 200’s of that vintage. The insulation fell off as soon as I attempted to remove it from the package.

Steve