Have a look here
First thing I would do is check to make sure I have power and a good ground on the
ignition module.
The easiest way to do that is with a 12VDC meter. Place the positive lead (RED) on the white wire at the coil. Place the negative lead (BLACK) on the aluminum plate of the ignition module. Then turn the
ignition switch on and it should read 12Volts. If it does then the power and ground it good. If it doesn't then move the negative (BLACK) lead to
engine case or frame ground. If still no 12Volts the +12V feed from the
ignition switch is not happening. If there is +12V when you move the negative lead to the
engine case or frame, then the
ignition module is not grounding properly. Clean all the contact surfaces.
Next test if 12v and ground are good.
Remove the mounting screws from the
ignition module and tilt it out. With a
spark plug attached to the coil and the threads of the
spark plug grounded to the
engine case, hold the
ignition module so it if grounded. Turn the
ignition switch on and place the rotor magnet next to the ignition module pickup sensor. Move the rotor and magnet around in front of the sensor and look for spark at the
spark plug. Note it should spark when the magnet moved across the face of the sensor.
If the above test does not produce spark the ignition module needs to be tested next. Disconnect the blue wire from the coil and connect the 12V meter negative lead to the blue wire coming from the
ignition module. Connect the positive lead of the meter to the
white wire/+12V wire. Then while holding the
ignition module to ground, move the rotor magnet in front of the sensor. The expected results are as follows. With no magnet in front of the sensor the meter should read 12V and when the magnet is placed in front of the sensor the voltage should drop to 0V. Once the magnet is move from in front of the sensor the meter should read 12V again. If this happens, the
ignition module should be fine indicating the coil is most likely the problem. 99% sure the coil.