1991 Force 150 w/Thunderbolt Ignition - Converter box issue

Hi,

I am working a 1991 Force 150 w/ thunderbolt ignition. This particular motor has a converter box that take 12V DC voltage supplied at the starter solenoid and converts it to AC voltage for the switchbox. Can anyone tell me how this unit works internally? I believe that it is killing the battery. The battery loses its charge overnight if everything is hooked up. When I connect the red lead from the converter box to the starter solenoid, it sparks. This tells me that it is drawing power from the battery. I would think this used should switch on an off (maybe controlled by the switchbox) but am not sure. Any help would be appreciated.

Thanks,
nate

Re: 1991 Force 150 w/Thunderbolt Ignition - Converter box issue

HUH?

Nate: I think you have it wrong. I have never seen a late model STOCK ignition that uses battery voltage. The red lead should be coming from the rectifier which converts AC voltage at the stator to DC, charging the battery. Ignition should be self energising and totally independant from the battery charging circuit.

Once started, the engine should run with that red lead disconnected and if you test the rectifier, most probably it has a short in it. If not the rectifier, look for a short in the wiring OR an accesory wired to the "B" terminal on the ignition switch. For example: A tachometer with the power lead attached to "B" instead of "I" or "A"". The "B" terminal is directly connected to the battery through the red wire on the solenoid and always has power, even with the switch turned off. Thus: Anything connected to it will also always have power and thus drain the battery. The "I" or "A" terminal only has power with the switch in the on or start position.

Re: 1991 Force 150 w/Thunderbolt Ignition - Converter box issue

All of the Thunderbolt ignition systems except for the 150HP used on the Force motors are alternator (stator) driven ignition systems. The Thunderbolt ignition system on the Force 150HP motor is the only battery driven CDI ignition system. The stator for the 150HP Thunderbolt system only has one winding with two yellow leads for charging the battery. To supply the ignition voltage, the converter box takes 12VDC and converts it to AC voltage. A transformer in the converter box steps up the AC voltage (DC voltage cannot be stepped up) to approximately 280 volts. The AC voltage is then converted back to DC (AC voltage cannot be stored) and stored in a capacitor inside the switch box. The ignition trigger signal causes the switch box to discharge the stored voltage to the primary coil winding. There is no switch on the red lead from the starter solenoid to the converter box. There are some SCR's (electronic switches..silicon controlled rectifiers) in the converter box that are controlled by the ignition trigger signal to enable this process. Maybe one of the SCR's is shorted causing the converter box to always be "ON". Basically, the ignition trigger signal controls the ON/OFF operation of the Converter box, and discharging the stored voltage in the Switch box to the coils. To be sure, disconnect the Switch box and from the Converter box and see if you still get a spark when you connect the red lead from the Converter box to the starter solenoid. If you do, then I would suspect that the Converter box is the culprit. If it does not spark, then I would suspect the switch box, or maybe mis-wired?