Once I get it to run good at high speed I lift the plane up, runs good tip it down the engine wants to die. I tipped it down and adjusted the high speed needle until it ran good, tip it up the rpm changes but still runs. In flight it will run good all day at ½ throttle. At high speed it will run for a short wile then quite if I don’t cut it back to ½ throttle. Could
PA You can throw plugs at it all day and not fix your problem. You have already found your problem..........It's all about tank position..............The upright mount change has put your carb up too high. With that wing saddle and short cowl section your tank has not much room to move.
Since pointing down or up and changing running so drastically tells you it is all about tank. Have you even touched the low speed needle ? Your fix will be ,side mount the engine, or even inverted to get carb down in level.............