RE: OS 1.20AX Unexplained Flameouts.......>>>
My experience with glow engines using a Pitts style muffler has been that there is insufficient muffler pressure to sustain WOT. The test for this is to see if you are able to run WOT and tune to overly rich. If you can, then you likely do not have this problem, as the tank is receiving enough muffler pressure. If it does not pass this test, the solution I have used is to plug one of the 2 exhaust stacks.
Good luck.