Hi Chris,
Disassemble your carb and look at the main jet. Directly behind that is another jet that, if plugged, will cause exactly the symptoms you describe. Remove and clean both jets (the smaller one takes a smaaaalllll screwdriver!), reassemble, and adjust you idle screw if needed. As mentioned, thoroughly clean the tank and petcock and add an inline fuel filter or you will repeat this process again and again.
Good luck,
David