It's in my experience that my DTR never started without choke, so that's normal. It needs to get to temperature and then you can remove the choke.
Sounds like you need to strip and clean your carburetor, based off what you've just said.
It could be float level height if it's just shutting the fuel off before it's even getting a chance to get into the bowl.
Strip the carb, removing the atomiser and properly clean the carburetor in and out, being careful not to damage it as the components are brass and delicate.
The engines are very basic and provided you've got compression, spark and fuel ,it'll run.
If you can confirm that it's got spark and fuel, then check the compression for the engine, should get around 140PSI. Anything below 90 PSI and your engine is going to need an overhaul.