Small Engines (Lawn Mowers, etc.): MOWER WONT IDLE, craftsman riding mower, briggs stratton

Question
I HAVE A CRAFTSMAN RIDING MOWER WITH A BRIGGS & STRATTON 8 HP ENGINE. THE ENGINE WILL NOT IDLE PROPERLY. IT RUNS WELL AT FULL SPEED, BUT SPITS AND SPUTTERS WHEN SLOWED DOWN TO IDLE. MY INFANT SON WAS MESSING WITH THE SCREW ON THE CARB WITH HIS TOYS AND I DON'T KNOW WHAT HE DID.

Answer
Hi Fran,

The large high speed mixture screw is initially set at 1 & 1/2 turns out.  Then adjust it to give good acceleration and top speed, while not closing the screw more than you need to.  The smaller low speed mixture screw is set at 3/4 of a turn out.  Adjust that, to give a smooth idle.  The 3rd screw, the idle speed screw, is set to give a low idle speed without stalling.  

Let me know how you make out.
Michael