I have cleaned the carb after my crashes and that was long time ago. I let the engine rest for 20 - 30 min after a 13 min flight. I have a big tank to fly up to 15 min, and I think the clunck is working ok since in the first two flights I do all kind of acrobatics, specially hammerhead. I don't think I have leaking since the firewall is always dry after each flight. I have a 13x6 prop, and I set the high speed neddle at the top of high pitch whine. If running too lean is the problem, why the first two flights are ok? My engine is mounted at around 270 degrees, would that be a problem? Attached is a engine size vs prop size. I think I am within the range....

Thanks