[redmodelt]

I think in one of the links I posted there is a diagram how to test using a spark plug, not the one with the bent wire. Each time the roller or brush passed over a segment in the timer it closes the circuit to ground. Connect the + to the terminal and - lead to the head, connect the wires to the plug(s), use a jumper a wire to any of the timer terminals to ether the head (ground) or plug base if not mounted in head. By moving the jumper wire from terminal to terminal you can check each plug/coil. The coil box is not the ground as the coils are isolated from it.