I guess it's just a real crap shoot with that engine, I have the same Tower RTF. It took a friend of mine all of about 3 minutes to tune it to a nice idle & smooth transition & it's ran like a raped ape ever since. Not a deadstick one to it's name. He did this as another guy was telling us what a piece of crap engine it was & how we would never get it to run right. Lol he slinked away rather quietly after it was all dialed in, in just a few minutes.