ORIGINAL: blw
I guess they are run in, but these have chrome liners and you don't completely break those kinds of engines in with just a few flights. The ones I've seen also have a fair amount of pinch too.
I have a .455 and a .46NT myself, and both are great little engines. The .61 and 1.00 engines did ship with o rings missing in the carbs for a spell, but that is easy to fix. From what I've seen on those 4 models I mentioned, they all need a hotter plug than the OS 8. The OS A3 does wonders with them. The .455 and .46 responds well to the Towers muffler too.
First thing I would do with those engines is to take out the OS 8, prop it right, and then see how it performed.
If they knew that the o ring was missing, I sure wish that they would have said something. I called off and on for over a quater of a year. All they kept saying was send it in. They could have said "we will send you a o ring"! They also said that I was the only one haveing these kind of problems with thw 1.00. We know now that was bull
I have tried several plugs. For Me type "f" is only one that works all the time.
john