"Jim Burns" wrote in message
...
One of the tachs in our Aztec has been acting kind of flakey, usually
reading too high when above 2100 rpms, (I've checked it several times with
an optical tach) so I've been contemplating our options of replacing both
tachs with a single dual needle tach. This would open up some panel space
allowing me to spend ludicrous AMU's on another toy.

One option is to simply get a mechanical dual tach and connect both tach
cables to the single tach but I don't know of a dual recording tach that
has
dual hour meters. Anybody?

I don't believe you need a recording tach. Most twin engine retractable
aircraft only record "flight" time and have a squat switch installed that
powers the Hobbs meter when the aircraft is airborne. Just don't forget to
disconnect the power to it while you have it up on jacks doing MX with the
battery on.

Allen