I had one of these that was a major pain my my fanny. It was doing exactly the same as yours and I tried everything to get it to run properly. The best I could do was to get it to run at about 50%. After much agonizing I finally sold it for what I paid for it. I have no idea if the buyer ever got it running correctly after that.
If you don't have any luck after trying these suggested fixes, I would consider taking it to a competent gunsmith. I'm sure there is someone out there that can make these lemons run. It sure wasn't me.
