You have an apparent usable fuel problem. At full throttle from take-off to touch-down, you should get a minimum safe endurance of 14 mins flight time with at least 1 minute guaranteed reserve for the circuit from a 12oz tank running an .46AX hard.

Start with checking over your fuel tank overflow pipe height to ensure you are getting 12oz into the tank. Then check the feed pipe to ensure the pickup is not kinking and is sufficiently distanced from the tank walls/corners to foul feed. Then cross-check the pressure line to ensure it's not coming off in flight causing a premature dead cut. If all of these check out OK, richen the high end N/V 3 clicks rich of peak rpm, even more if that AX is new and hardly had any fuel through it. If that's the case, suggest using less nitro and more oil content in your fuel, or richen the **** out of it and run a conservative load/rpm until you've clocked up a couple of hours runtime on it.