Hi Allen:
Sometimes it is the small things that confuse us. I have had this problem in the past and I have found that the engine was not getting enough fuel. It has been a faulty nva and sometimes my fault. I was asleep at the switch and failed to notice that that particular engine needed the needle opened many turns to get the engine to run correctly. Take a walk on the wild side and try replacing the nva and/or opening the needle many more turns than you think s correct. These engines are very simple and it is us who are misinterpreting what they want. Let us know what you find to be the solution.
We are having a club stunt contest, old time pattern, and a club combat, run what you brung, contest this Summer. Nothing high tech but just a FUN get together. Would like to see you join us. Remember, it is a very easy trip for you to attend our new flying site.
Be well,
Frank McCune