I have this exact same auger and asked a question somewhat similiar to this. It may be on page 3 or 4 but if you need more help go there.
I did the some thing as Big Fish Hunter. I turned it all the way in, and then turned it out about 1/4 to 1/2 turn at a time until I found a happy medium.
Mine would bog out or die after a few inches of drilling.
I was able to get it running good again while drilling, but now it's starting very rough and dies much like yours has been if I dont keep the throttle full on it.
If you work at it for 10 - 15 minutes you should be able to get a setting that works. I'm in the same boat you are, so I know how badly you want to get it running good again!