Small Engines (Lawn Mowers, etc.): Air/Fuel Mixture Adjustment, air fuel mixture, pedel

Question
I just bought my son a go kart equiped with a 5.5 hp 4 stroke 1 cylinder OHC WKR engine (163cc).  The first time I started the engine, the idle was so high that I had to shut it off immediatly so it wouldn't take off on it's own.  I mistakenly started adjusting the two screws on the side of the carburator trying to lower the idle.  Instead, the engine started running very rough.  Now it cuts out when the gas pedle is barely touched and will run smoother when the gas pedel is pressed down fully.  The idle is still very high and the cart goes about 10 MPH without even touching the gas pedel.  If you could advise me as to how to readjust the air and fuel mixture screws I would be forever in your debt.  

Answer
The initial settings for the mixture screws should be 1 1/2 turns out from lightly seated.  Then adjust the idle speed so it is below the clutch engagement.  The low speed mixture screw is the one closest to the cylinder.  Then the low speed should set so it is only rich (rich is turning screw out) enough so the engine doesn't bog when the throttle is opened quickly.  Once you have the low speed correct, it may be necessary to re-adjust the idle speed.  Then support the go-kart on blocks and make sure it can't take off anywhere.  Open the throttle wide open and start turning the high speed mixture screw in until engine reaches maximum RPM, then open it 1/4 of turn.  This will provide sufficient enrichment under load.  Hope this helps.