An engine/tachometer concern.
On takeoff with full power applied MP goes up normally and remains constant. However, RPM increases to about 2500, then fluctuates between 2300 and 2500 for about 3 seconds, then increases to 2700 and remain there. There is no apparent decrease or fluctuation in power output.
In flight RPM behavies normally. And, this anomaly does not occur during power increase for a go-around or on a touch & go landing. But, it does reoccur during a taxi back and takeoff.
Should we be concerned?
