My NC50 Express will only start with the aid of starter fluid sprayed into the air filter/carb. Then it will only remain running if I keep the gas at 1/2 or better throttle. After it does warm up, it idles better, but is still unreliable. I have cleaned and re-gapped the plug and points and throughly cleaned out the carb. I am looking for suggestions or a reference to someone in the Atlanta Georgia area that can take a more knowledgeable look at it.