In the last couple of flights in calm air, level with AP on, with constant speed prop set at 2300, I noticed the rpm jumping down as low as 2270 and high as 2310. Frequency is at least once every minute. It jumps quickly and most times its almost unnoticeable unless Im looking at the EFIS. Engine or oil temp doesn't matter. Nothing out of parameters on the CHT or EGT.
On a short flight to get fuel yesterday I ran at 2400 and it stayed dead on, but started fluctuation again when set at 2300. Just did an annual and thought I would find something up with the prop governor or plugs.. but nothing so far. I have a GRT EIS and Dual EFIS set up with 205 hours on a O-540.
Update EFIS software? Check mag timing? More test flying tonight at various RPMs.
On a short flight to get fuel yesterday I ran at 2400 and it stayed dead on, but started fluctuation again when set at 2300. Just did an annual and thought I would find something up with the prop governor or plugs.. but nothing so far. I have a GRT EIS and Dual EFIS set up with 205 hours on a O-540.
Update EFIS software? Check mag timing? More test flying tonight at various RPMs.