Voltage on kill wires from ignition module

[DudeAbides]

Is it normal to see voltage across the white wires from the ignition modules and ground?

I am getting 12-30 volts while the engine is running. 1989 85hp with presto lite ignition

Harness to helm is disconnected so I am trouble shooting by starting and killing the motor with a jumper at the terminal.

Motor is running better than ever since disconnecting the harness so I am sure there is a problem there to deal with.

I also had a situation where an ignition wires insulation was burned and likely shorting to the block. That's fixed also but wonder if the module
Is shot now from that?

 

[Jiggz]

Yes if the motor is running there will be voltage on the kill wires but not when the engine is NOT running. One thing you want to check with the rest of the wiring is those wires that are rubbing off against the engine block and could have worn out insulation and shorting to ground. This is a very common cause of electrical problems with this ancient motors. Lol

 

[Frank Acampora]

Your symptoms puzzle me because the white wires are the kill system. When shorted to ground through the blue wire they dump the capacitors to ground so the coils can not fire. The capacitors, however are charged with about 250 volts from the stator. Thus, readings it should be this higher voltage. Are you using a meter that captures and saves voltage spikes? The voltage rises and drops so fast that a regular meter will not show it. Thus: you may be reading a much lower voltage. And, by the way, do not touch the white wires while the engine is running. You WILL get a thrill. I made that mistake while working on an ignition switch and shorted myself through both "M" terminals.

 

[DudeAbides]

Thanks Guys. This is very Helpful information.

Jiggz. After finding the damaged wire leading to the coil, I went through each wire carefully to make sure they were not compromised.

Frank. I was just using my regular meter. I was surprised to find voltage, but now that I know it should be there I will go back with my DVA and check it out.

It would be interesting to see if I am getting 250v from modules white wires. because I still have yet to see any voltage come from the modules output (while cranking)

After finding that there was an issue with the harness, the motor starts better than ever and runs better than ever. I was sure at this point that I would see output voltage from the modules with my DVA, but still nothing. I also made the adjustment of checking with the black lead attached to the terminal ground as opposed to the ground that is attached to the cover plate.