I have a tower .75 I just flew on my big stick .60, for the first 2 tanks this was the worst running glow engine I have ever heard. It missed and coughed and tried to die so much I started to wonder if something was seriously wrong. The only way this thing would run was so rich it was making a huge puddle under the exhaust. I ran a 3rd tank through it and about halfway through it started to clean up so I finally could lean it a tad and it actually would stay running. By the end of the third tank it was having exactly the same problem you describe about your TT.

I would not worry so much, after another tank on the ground a new plug and 4 actual flights it is running great in every way. My theory is that some engines are very tight and really need a much longer break in time then the manual would have us believe. This one said I could do it in one tank. I ended up with close to a gallon of fuel through it before it behaved like it should.I have my suspicions that it is not even close to fully broken in.