Engines Running Rough on Hose

[DRock3d]

When doing my oil change and spark plugs on my new to me 2013 242 LS it seemed like the engines ran rough and had a little shake when running on the hose. Is this normal or should they run smooth as glass?

 

[haknslash]

They should feel the same but they will sound a lot louder out of the water. Like a can of bolts and marbles being shaken because the impeller is not mufflered by water.