So was it not even leaner to begin with? You missed my earlier points. The base needle positions on most Walbro carbs is 1 1/2 turns open. That will get the engine started. Everything after that is tuning since the engine is not in any particular state of tune when you get it.

Visit the link to Ari's site. Worst you can do is peak the high AND the low. From that point the low needle can only go richer to hit happiness. If the high is peaked it's where it needs to be. Go slow, and do it small. Those 1/2 turns you did in glow will kill you with gas. Once correctly tuned, 3/8 of a turn on a high needle will often shut a gasser down.

Once you learn the very minor differences in the way glow and gas tune you'll hate glow because gas is easier and doesn't change on a flight to flight basis like glow often does. It's normal to not touch the needles on a gasser for a year or more after it was correctly tuned.