a few times now on the 70's hondas i have seen spark plug wires where the insulation inside has turned to a black goo. i assume this is a bad thing so i swapped the coils. anyone out there seen this before?
I have seen it and just assumed it was a nasty form of corrosion. I have trimmed the plug wire to get rid of it and reinstalled the plug caps unless, the screw part was corroded too. Then I installed new caps into the trimmed wires.