Today i had my g26 on the bench (second time running) And i noticed that at half throttle it stumples, sometime it would die. It did not run well at half throttle. Idle was fine and the high end was fine what could be the problem?

Two things come quickly to mind.

1) The engine is still really new and all the parts are not well seated yet.

2) The mixture needles are not quite where they need to be.

Unfortunately, number two can not be completly cured until there is a little more time on the engine. The best break in you can do with a gasse will be done in the air, where proper thermal cycles will be maintained. Just don't run the engine lean during the first few gallons of gas.

Sounds like the carb is opening backwards..Close the throttle, take the arm off, and turn the shaft as far as it will go the other way, re install the arm....
New engines run just as well as older ones, just not quite as fast...

RCIGN1 I looked at what you were talking abought.When the throttle was fully closed i could look down the carb and see the bottom of a screw so i fliped it around and now i see the top of the screw when fully closed (small screw in the center of the little flap that opens and closes on the carb)

I might have made it worse, could have been right at first...If the carb is off the engine the head of the screw will show when you look at the bottom of the carb with the throttle closed..Can't think of anything else that would cause what you describe...Both needles shoud be around 1 1/2 turns open..The stock carb on these is a little strange in the way it works....The disc uncovers three small inline holes in the venturi as it opens...After about 1/3 open the holes are fully open..At half throttle both needles affect the mixture.....

I will try some new fuel the stuff that i put in is a little old.