Put in a new glow plug. Then follow the procedure below. Are you sure your air filter never came off? Dust in the needles is a nightmare. If you think that might be a problem, then take apart the carb first and clean every part with alcohol and an air hose.
Reset your needles to factory break in settings, then do it in this order:
Adjust your LSN and idle screw till it idles well and will run up to half throttle. (get it to running temp before you finalize any settings) When it idles properly, throttle it to half and see if it stalls or bogs down. If it stalls, it's too lean. If it bogs, it's too rich.
Now go to full throttle. This is when you adjust your HSN. Same thing. If it bogs, it's too rich, stalls, it's too lean.
When it seems to be running good, pinch the fuel line. It should speed up slightly and then stall within 3 - 4 seconds. If it stops quickly, your LSN is too lean. If it takes longer, the LSN is too rich.
Drive it for a while and then take a temp check to make sure it's at the proper temp. If it's too hot, richen the HSN.
You will have to make small adjustments on the HSN almost daily to compensate for outside temperature and humidity.
By the way, the factory settings are for break in, or a starting point if you really messed things up. Once an engine is broken in, don't expect it to run right by going to those settings.