What kind of fuel are u using .

R u using the home built fuel or a specific brand .

If hoem fuel , check the percentages.

As u have mentioned about the tightness of the needle, it is advisable to have it 2.5 turms from the closed valve position .

Another reason , coudl be, you have over flodded the carb. u woudl hve to open the plug & drain the fuel out by invertingthe plane . But before u do this make sure the valve is tighetened so all ur fuel does not leak . Now invert the aeroplane.

Before u start the aircraft, open the carb aperture full and palce ur thumb over the hole and turn the prop a coupel of times( make sure the glow plug is not plugged) to move the fuel.

Now u can start the engine .

happy Flying.