Rattling noise (seems to sound like its coming from engine)

[Ducky3321]

A month or so ago one of my spindles broke on my deck. The bolts snapped in half which caused the blade to get stuck in the ground which also knocked off the engine. It runs fine but if I turn the choke around 3/4 of the way up I hear a rattle noise coming from the back of the engine (I think). But if the choke is anywhere except around 3/4 their is no rattle. I thought it was something to do with the brake because when It's in park and not moving theirs no rattling noise. But once I start moving it rattles. But I have checked over everything and only thing I can think of what it would be is something to do with the engine pulley. Thanks for the help.
Poulan Pro- PB19H42YT
Briggs and Stratton - 31P877-0608-E2

 

[bertsmobile1]

Chokes have 2 positions.
On to start
Off to mow
There is no reason whatsoever to run a mower engine at 3/4 choke in fact it is a really good way to shorten it's life considerably.