Help
I am flying an Aeroworks P51 with a DA50, Jtech Pitts muffler, Xzoar 20X12 prop, RedLine 40 to 1 on reg gas. Engine runs great for about 5 minutes then will lean out overheat and die. When I take off the engine is slightly on the rich side and as the flight progresses it begins to run stronger (leaning out) and then will quit. I know a gasser shouldn't start out the flight rich and go leaner like a regular 2 stroke non pumped nitro engine. I checked out the plumbing and clunk in the tank and its perfect. No leaks. I pulled the carb apart and the screen looked dirty and I removed it and have been flying it without the screen. The problem worsens when the ambient temperatures get hotter. It's overheating. I have the cowl opened up as much as possible. I flew it 3 flights Saturday before noon and no problems then afternoon temperature increased 10-15 degrees and then it started acting up again. I have lots of experience with DA100 & 150 and have never had this problem. Any ideas?