RE: Evolution 45GX will not draw fuel ???
Walbro 613 is not standard on the 45 engine. Open the idle needle more. The carb depends on sufficient fuel flow from the idle needle to get the WOT mixture right. Climbing to 2200 rpm after throttle down also points towards too lean idle settings.
Power loss is quite normal in a two stroke as it heats up, especially with restrained engine operation on a test stand, when the engine can get VERY hot quickly!