In article W4NOa.13721$N7.2280@sccrnsc03,
"The Flynns" wrote:
I've had the tach checked and you are dead on- --100 rpm low consistently
across the range. (Ken Blackmon did the last one at annual.) I've wondered
about getting it overhauled in the winter when I get the plane painted.


I would seriously consider replacing it or supplementing it with a good
digital tach. I had the tach replaced in my PA-28-181 a few years ago
with a brand new Mitchell tach with the painted faceplate. Despite what
the calibration card said when it was installed, it didn't take long for
it to drift almost 100 RPM low at cruise. Any mechanical tach is is
going to have some drift which is only going to get worse over time.

I did not put a digital in because my mechanic at the time discouraged
it. I now basically believe that he did that because he didn't want to
do the extra work to put in the digital tach.



JKG