This seems unusual....not a normal old U-Joint/Gimbal Bearing event.
Vibration Problem while Turning 2007 Volvo-Penta 4.3L SX-A
I bought my latest boat (Chaparral with 4.3 Volvo-Penta SX sterndrive) new in 2007; it now has about 50 hours total. Before, I had an ?87 Sea Ray for 20 years. The...