Ok...the plot thickens.....I removed the rx from the wing and let it hang free in the air......started it up and everything was fine. I had the rx wrapped in foam and now am wondering if it was packed too tight. Now I seem to have a new problem....I can't seem to adjust the high end to run smoothly. Acts just like an air leak. I tightened all screws on the engine, which were tight, changed the plug, changed the carb fuel line. I'm seeing no bubbles in the line but maybe I'd better tear apart the tank and check those lines.....Geeeez, this plane has always run and flown well and now its kind of falling apart..........Hmmmmmm, could this be a sign that the valves need adjusting? hey, any and all opinions welcomed!