It’s the plastic bushings in the pivot joints. They last about a year and you’ll know when they’re REALLY bad when they fall out on the deck.

^this, there’s a video on youtube on how to replace them. Horrible design with junk plastic.

The first thing I would do with every new motor, is take it to Boras Marine and let him fine tune the motor and they know every trick in the book to make it run smoothly. Most of them that had a reverse back in the day shook the whole boat. They would go in and adjust the brushes to stop that noise also. The rubber cushions under each through the top cap bolt was another key to stop the grind.

You can loosen the two screws that hold the rear of the motor housing to the main housing. Put the motor on constant speed, about 70%. While the motor is turning, carefully rotate the end housing clockwise and counterclockwise until you find the sweet spot that produces the highest speed and least noise. Many, many owners are not even aware that this adjustment is even possible, much less try to do it.
Two things!

1….don’t get your hands in the way of the prop!!
2….don’t forget to retighten the end housing screws afterwards.

You can also balance the prop using a lawn mower blade balancing stand. File a little off of the heavier blade until the prop is perfectly balanced.