hello all. I hope to get some help in this prestigious forum for connoisseurs. I have a problem with my O.S. 91 SuperPass II with pump. I moved the engine from one model to another model, I wish to state that the engine has just made 10 flights, and then 'again, on my new model performs well when it goes right all right, full power, no problem, when it goes into the top loop in the engine loses power and then again, even while maneuvering screw when upside down in the engine bay right now is fine. other even when they are with half power and give full power for about 3 seconds, the engine does not respond then suddenly goes at full speed. because all these problems with a paradigm shift? I hasten to add that I checked 2 times the tank and it is' okay. the propeller on the first model was a sulk 3blade according to a 2 blade of the size specified by the user of the engine, then adjust. the flight test and 'went perfect but I did not do any maneuver in flight, only regular flight as you can see from the video. Who gives me an advice to adjust my 91 best?