Flight Risk here with an update. I rechecked all hoses and needle valve and carb for leaks. I drained the crankcase from all the old oily fuel. Mounted the engine on a test stand and ran a few ounces of fresh 10% nitro, 20% oil through it. It ran great as new. Mounted it on the plane and filled the tank with the fresh fuel. It started and ran great for about 5 minutes then quit suddenly as usual. I opened the throttle and looked into the carb and the fuel was percolating. I drained out what fuel i could and spent several minutes trying to start it again. It would run 5-10 sec. and quit. Seems like it is drawing in fuel faster than it can burn it and the rest is building up in the crankcase and percolating out the fuel to leave the oil. I have tried leaning out the engine as far as I can without dying. I've tried several plugs. Evidently the fuel isn't the problem. I guess I could try a hotter plug (i've used an A3, A5 and Fox Miracle plug) or try to find fuel with 10-15% oil. Back to the drawing board.

FR