RE: Motor cuts out at half throttle. (Phoenix 25 controller)
You don't mention how you're configuring the ESC, whether by PHX Link or through the "transmitter" interface. Configuring from the transmitter is confusing, and it's very easy to make a mistake. Many a 4-letter word was uttered during my first foray into configuring a Phoenix 80... You're sure you have the cutoff set correctly?
There may be a software issue with the ESC, then. Shawn Palmer will be able to help you out. Wish we could get him over here, but he's firmly entrenched at that "other" site.