carb adjustment?
 

Hi all, I've read the carb adjustment post numerous times and think its my carb but someone with a little more experience always helps.

I bought the bike (sunjazz 250cc) around xmas and had a bike mechanic tune it up and adjust the carb. It ran perfect until the hot weather, Idles fine, runs strong, BUT when im in second gear or higher and I'm going to slow down or stop as soon as I let the clutch in It idles down and stalls and wont start for at least 2 minutes or so. I checked spark, it's ok; I checked the air filter, it's ok; I regapped the plug that was a little open but looked fine; I checked the carb for dirt and cleaned it.

Otherwise am I correct deducting that the carb needs adjustment? should I just adjust the pin height? Up or down?
Thanks in advance, hivoltage98