Engine Knocking Due to Drivetrain or Propeller Damage

Inspect the propeller for physical damage such as bent, chipped, or missing blade sections. Verify the propeller nut is torqued to specification. Examine the drive shaft coupling bolts for signs of looseness or vibration. Check the universal joints for play or excessive wear. Any misalignment in the shaft or damage to the prop can manifest as a rhythmic knock or vibration at high RPMs.