Big current draw when ignition switch turned on
 

I have the alternators removed and will be having them checked (neither of them puts out anything -- may have been damaged trying to charge a frozen/shorted battery). I'm getting a 6 amp (shows when I have the battery charger hooked up) current draw on the right engine when the ignition switch is in the first position (no measurable current draw when the left ignition switch is turned on). I have isolated it to the purple wire labeled IGNITION. According to a wire diagram I found on the net, this wire goes to the alternator, but interestingly, there is no voltage at the purple wire going into the alternator (voltage regulator actually). There was voltage on the red and orange wires going to the alternator studs. I could smell a prominent burning smell when I first put it in the water and was on plane, but couldn't narrow it down. The batteries finally ran out of juice and both engines stalled. This is on an '81 Formula with stock 260 Mercs.

Sounds like you may have a melted wire in the loom mbe?, or something wrong in your guage cluster? I would start at the key(remove the purple), check wiring through the guages, then the loom, finally motor harness, try to break it down into sections and trace it out. It doesn't change color unless someone messed with the wiring. Not the answer you were looking for, but should get you going till someone else chimes in. It is what I would do if that helps

OK, good suggestion, I'll give it a try, thanks.

6amp draw usually indicates a defective device somewhere or a short to another device feed. Do you have an electric fuel pump? Disconnect things like the blower and see if you get the same draw.

He isolated the draw to the Ign wire. Fuel pump/ blower operate from the 50amp circut on the engine. That leaves the guage package, loom, etc to check ending at the alternators

6 amps would be pretty typical of the current going through the coil. Most likley the engine stopped with the distributor in the part of the ignition cycle that is "charging" the coil. In the old days this would have been the points closed or "dwell"

The other one is most likley in the "points open" position.

Make sense? You can always pull the + lead off the coil and confirm. If the power is on you will get zapped.