Small Engines (Lawn Mowers, etc.): spark plug keeps fouling in lawnmower, honda gcv 160, spark plug

Question
I have a Husqvarna w/Honda GCV 160 engine.  It is only 4 months old and has fouled the spark plug twice now.  I took it to the shop where I bought it and they are dumb, they just keep changing the spark plug with no real explanation.  This last time they said there was too much oil in it, but I have never added any oil except when I first got it which was 18fl oz.  They just looked at the dipstick, which the lawnmower was tilted! Also it was blowing black smoke and sputtering.  I just got it back and it runs fine, but not for long...until whatever is fouling the plug happens again.

Answer
Hi,
 Are you sure that it is the right spark plug for the mower? It sounds like somthing is plugged up in the carb! Is it still under warranty?
Give me the Model, Type & code on the engine so I can get a little more info on that engine!

Curt
Central FL