Yes I realize the low speed needle is very sensitive. How Im tuning is at wide open, with the glow driver removed I slowly turn the high speed in (lean) until the engine runs at peak rpm. I then turn it back out until the motor loses about 3 to 4 hundred rpm (confirmed by my tach). The low speed needle is set at idle. There is a very small area where the engine runs fine. This area is about the range of a quarter turn. Anything outside of this and the engine simply wont idle. The best I've ever had is a idle for about 30 seconds, then it dies and fuel starts dripping out the carb. Once this happens, I have to remove the glowplug to drain the fuel from the plug. THe Hanger 9 p40 has the hole in the firewall where the bottle neck of the fuel tank fits through. This looks to be exactly centered with the spray bar in the carb. I do use a fueler valve which mounts between the carb and the tank. This shuts off fuel to the carb when you insert the probe while fueling. The valve is mounted about 1/2 inch above the spraybar. Im about to tear it back down to the firewall and remount the engine sideways. Yes Ill have the cylinder head sticking out the side of the cowl but at least then the exhaust will exit out the bottom. I hate to mess up the cowl but I'd rather it run correctly then to look cool. I can always just fly left to right and then come back right to left inverted so you wouldnt see the cylinder head, lol. Do you think a hotter plug might hold an idle better? What type of plug?