[TR] horn hook-up, battery found

[Randall]

> Question: why the
> difference?

I don't know, but I doubt it had anything to do with polarity.  The TR2/3
type horns are very prone to developing corrosion around the pushrod that
opens the contact points, so I would guess that it got stuck between the
first and second test.  The cure is to disassemble the points, so the
pushrod can be cleaned and lubricated.

> and had a CCA of 850.

It's worth noting, perhaps, that there is more to car battery ratings than
CCA.  CCA (Cold Crank Amps) is basically a measure of the battery's internal
resistance, and it certainly needs to be adequate for the purpose.  But RC
(reserve capacity) is the measure of how much power the battery can deliver
(much like the older amp-hour rating, but measured differently) and IMO is
more important.  

Since the original Tractor motor starter only draws about 450 amps max
(typically about 300 while actually cranking the engine), I would suggest
that looking for CCA of at least 450 and RC as high as possible might make
more sense.

> I don't suppose that many CCA could damage a un-adjusted TR3
> horn-do you think?

No, having too many CCA won't damage the horn.

Randall