I HAVE A EVO .46 AND MY ENGINE MAKES THE SAME NOISE. HAS MADE THAT NOISE SINCE I BOUGHT IT NEW. I LOOKED AT EVERY THING COULDNT FIND ANYTHING WRONG OR LOOSE OR OUT OF BALANCE. SO I PUT IT BACK IN THE MY PLANE AND I HAVE ABOUT 8 OR 9 GALLONS OF FUEL THROUGH IT NOW STILL MAKES THE NOISE BUT RUNS GREAT. THE MUFFLERS ARE JUNK I AGREE YOU HAVE TO PUT ALLTHREAD THROUGH IT SO YOU CAN GET IT TIGHT . AND BLACK STUFF IS FROM MUFFLER RUBBING TOGEATHER MINE DID THAT ALSO. I TOOK THE BAFFLE OUT OF MINE AND IT IS LIKE A DIFFRENT MOTOR. JUST THOUGHT THIS MIGHT HELP.