My wife and I have flown a J model Mooney for years and recently acquired a K model She has a difficult time pulling the yoke back with enough force during the flare, so she trims just a bit more nose up trim than needed while stabilized on final approach, requiring less pull force in the final flare. We often fly with just the two of us in the plane, and never reached the stop in the J, but we do in the K. And after about our third or fourth flight in the K, I could not get the trim unstuck from the full-nose-up position while trying to set trim for takeoff. The owner of my local Mooney service center said that this is a somewhat common occurrence. I pulled the belly panel directly under the trim wheel and freed the jack screw using pliers. It took quite a bit of force to break it free. He inspected and lubed the jack screw and recommended trimming manually when getting near the stop, to avoid jamming it using the electric trim.