I have a 1980 M20J that had a Plane Power Alternator installed in it before I purchased the aircraft. It still has the same voltage regulator and my mechanics are having hell getting the voltage to stay between 13.0 and 14.5. I am getting very erratic swings on my ammeter (from -30 to +30) and it seems to be making my autopilot porpoise pretty bad. I had the Century 41 AP rebuilt and that did not resolve the issue. I am convinced that it is an issue between the voltage regulator and the alternator, so I purchased the Plane Power voltage regulator that is supposedly compatible. Apparently the M20J model is not listed on the approved airplanes for this regulator, so the plane will be grounded pending an FAA Field Approval. This is a crock of crap because the M20F IS a listed approved plane and that is pretty much the same aircraft, correct?? Has anyone had these issues or tried installing this voltage regulator on the J model? I would appreciate any feedback I can get from you pro's.
Thanks,
Michael Reitz
1980 M20J
N3891H