Small Engines (Lawn Mowers, etc.): Snapper with 12hp Briggs and Stratton, snapper riding mower, briggs and stratton

Question
We were given a Snapper riding mower with a 12 HP Briggs and Straton Engine.  After the engine has run for a short time there is a high pitched, loud, squeeling sound and the engines starts to smoke all over a white smoke.  I immediately turned off the switch.  

What are some of the things we should check?  My husband thought it might be a belt, but I did not have the engine in gear or the blade engaged. The oil level is okay.  He's a pretty good handy man, and we thought he could take care of the problem with some advice.  Thanks.  

Answer
Definetely check the belt.  Make sure to check the deck bearings.  You can do this by dis-connecting the belt or removing the deck and moving the blades by hand.  You will have to actuate the mower deck pulley brake to check the bearings.  

Does your mower have a pull start?

Let me know.
Eric