Summer is here.

For 5 days now I haven't needed the quilt on my bed. Summer must really be here at last. I go flying in the morning to avoid the heat, nearing 80 degrees and 80% humidity.
The Fox .35 is still giving me trouble. I put in 3 head shims and a stock muffler to calm it down. On the ground it runs great. But when I pull the release the plane travels 30 feet and the engine goes into fast 2 cycle mode for the entire run. Not the famed thermal runaway as the engine isn't that hot at the end of the flight. I'm trying a different fuel mix. I'll try putting the original head back on as the hemi head is way too powerful and finicky.
I posted my question about nitro and oil on one of the forums and it has 2 pages of arguments so far. One respondent got a PhD friend to give an answer. I'm beginning to forget what I was looking for.