get rid of that auto choke carb for now and put the original one back on. Make sure the needle has the clip in the middle for now. As others have suggested, get an NGK plug. The ones that come with these kits are generally very poor and often bad out of the box. Even though you can create a spark in open air, it may be unable to spark under compression - known as blow-out.
A unique problem with that particular cylinder design (CDH LD100) is that the intake flange has VERY thin flanges at the corners of the rectangular intake port, and it is very well known to leak. There just isn't enough flange surface there.
A unique problem with that particular cylinder design (CDH LD100) is that the intake flange has VERY thin flanges at the corners of the rectangular intake port, and it is very well known to leak. There just isn't enough flange surface there.