Have you flown that Menz 22-14 with success in the past? In other words, is this a new problem with a known engine / prop combination. That seems like quite a load for that engine. I've flown the Q 75 quite a bit but always with something like a 23-10 or 24-10 and even then the 75 turned those props in the high 6800 to 7200 range if memory serves me well. I'm not sure you have an engine problem or maybe its just overloaded with too much prop.

I currently fly the Q 75 in a Z Skyraider.