I bought a used 2001 (i think) Kymco 90 quad for my son. It ran good for the first 10 hours or so. Now it starts, idles and moves. However, when you get to 1/4 throttle it almost stalls and just putters. I put a brand new carb (with new electric choke as well) on it and it does the exact same thing. I pulled the plug and it looks good... Without randomly repalcing the coil or other parts i was hoping for suggestions. If any one has any ideas or thoughts it would be greatly apprecited.

thanks