I had previously reported my tach reading about twice as high

[Richard Lancaster <RLANCASTER@ntia.doc.gov>]

I had previously reported my tach reading about twice as high as it
should, on my 67 B.  Someone, Barney I think, provided a nice
explanation of the internal adjustments available, but first I tried
to just tighten up the connections at the back.  As I tightened the
little knurled round nuts, the tach returned to normal!  So the
grounding problems even affect the tach, although why it ran at all
with a grounding problem is beyond me.  Hope this helps others,
before they have to tear the whole thing apart.