OK here is what I have and here is the problem I run into

I got the ultimate ultrafly and I am using a himax HC2808 brushless motor. The esc is a E-flite 20 amp brushless and the battery is a 3 cell 11.1v electrifly Li-Po.

The problem is when I go to fly and the throttle is about half way to full, everything shuts down.

I was tolled by a hobby store guy that to many amps are being pulled through and that I needed to use a smaller prop, well I tried an 8x6 which at half throttle barely moved the plain and then it shut down just like before.

What can I do??? I want to fly...