After removing the prop, mark it with a Sharpie across the hub and on the prop itself. After running the motor for a bit, remove the prop and see if the marks are still lined up. If they aren’t, you’ll know that the rubber hub in the prop is slipping and needs repair. This method only works for props equipped with a rubber hub. If your prop is solid and slips, it could be the shear pin has done its job or something inside the gearcase is wrong.
Here’s what crosbyman means.
