Ok a few things I'll point out to make sure you left no stone unturned
1) Have you gotten a rebuild kit for this carb and replaced the needle and seat?
2) You should have the gas all the way open when running the machine and making adjustments.
3) Have you let this carb soak overnight and then blow it with compressed air? A simple spray of carb cleaner is not enough to get into all the small ports that may be clogged.
4) Are you making adjustments as soon as you start the engine cold? If so your never going to get anywhere, for adjusting the carb initially set it to factory specs then start the motor and let the engine run atleast 10-15 minutes , even if it runs like crap keep it going until it gets warm to operating temperature , once the engine is warm start the coarse adjustment first (bottom screw) allow the engine to set itself for about 30 seconds before making another adjustment, if you make adjustments too fast or on a cold engine you'll never get the engine set right.
Brian's prices are more than fair, gives excellent advice/support, and he provides excellent service. Try the rebuild with the help of the forum.