Went flying today and think I found the problem. First off I changed the engine in the SE to a Magnum 46 XLS that I had and it ran flawless at all throttle settings and attitudes. That pretty much eliminated fuel delivery problems. So then I put the GMS back in, adjusted high speed needle to 14K RPM then richened to obtain 13.4K Rpm at full throttle, pinch test was good. Now the problem, still on the ground I reduced carb to about 1/2 and 2/3 throttle and when I pointed the nose vertical engine would slow down; LEAN! At full throttle this would not happen. Knowing that the low speed needle is not just for idle I started turning the low speed needle out until RPM did not change when I pointed nose up at partial throttle, had to readjust high speed a few times during process. Flew it with this setting and engine ran great without dying out as it had before. Now the problem, with the low speed needle set so the mid range is good it is very rich at idle and does not transistion good. Everything is sealed good except for the well known front bearing leak, maybe the idle problem. I have been around quite a few engines and it seems like the problem with these might be resolved if the carb barrel cam slot was cut to give more travel to the low speed needle. That is let it close more to get a good idle but move out of the way quicker for enough fuel at mid and high speed. I have one thought I may try, file the bottom of the spray bar to about a 45 degree angle pointing down. My thinking is this would allow more fuel at part and full throttle and I could still screw the low needle in to get a good transition. Any thoughts on this?
Now for the ugly! I was having fun doing rudder stall turns with down spirals. Did one rotation to many, SPLAT! No more SE.
UPDATE after examining the carb more carefully I see that filing thr spray bar would let more fuel in at idle also, so I think I will taper the last 1/16 of the low speed needle a little more. This should allow the idle to be set leaner but allow more fuel as the carb is opened. I am also going to seal most of the slot between the front bearing and the intake port on the crank, I think this is where most of the air leak comes from.