If you actually getting more vibration than normal and a fluctuating
tach then there is a problem that needs to be looked at before further
flight.
Michelle

wrote:

On 5-Sep-2005, "att news group" wrote:



Any thoughts or ideas?




A fluctuating tach with no other indication of engine problems is probably
caused by a binding tach cable. Fairly easy and (by airplane standards)
inexpensive to replace. However, if there was an accompanying unusual
vibration, it could be any number of things. Did you try running on only
left and right mags? If the problem is anywhere in the ignition system
(mags, ignition harness, plugs, that will confirm it and tell you which side
has the problem.