This past winter I purchased a Arrow trainer with a Evolution TPS .46 engine and a JR Quatro radio. From day one the airplane didn't perform, the engine never ran right, I never got a complete flight.We sent the engine back, they put a new carburator on it and said it was fixed. In the mean time the guy at the local hobbie shop loaned me a .51 to use while my engine was being repaired so I could get some stick time in. While my instructor was flying it with the .51 on it the radio quit during a dive, the plane went vertical into the ground wide open, it was quite spectacular. I then sent the radio back and they found that the reciever was defective, the guy at the hobbie shop said that JR would make good on the radio but the plane was my responsibility, I then bought a ARF to replace my crashed plane, this was when I kinda lost interest.I have since decided to try and learn to fly, I took the flywheel off the TPS .46 and replaced the prop with a 2 blade 10 x 6, I also took the baffel out of the exhaust as it was causing so much back pressure that it caused the muffler to try and separate no matter how tight the screw was holding the muffler together, now the motor wont idle, it runs great wide open. The only way we could get it to idle somewhat was to close the idle screw all the way closed, it still wont transition to full throttle well at all, any suggestions will be greatly appreciated, thank you