After this beast sat for 4 years, I had the pleasure of bringing it back to life. Normally I choose to install a NEW carburetor. However $1400 dollars is a wee bit high. So deep clean and rebuild... still pricey. After reassembling and close inspection of all connections it fired right up. But it backfires on dethrottle. Also it seems sluggish. After numerous adjustments it refuses to improve. Air screw is 2 1/4 out.
HELP any clues?

 

Check for any airleaks in the exhaust or carb. Same thing happened to me on my mojave. Just had a hole in the exhaust.