What is the pattern for tightenig the bolts on top of the engine? Or is it just criss cross and even? Also engine is killing out when second gear grabs?

Criss Cross evenly, you can't realy ruin the head on an engine this small by tightening the bolts in the wrong sequence.

criss cross and tighten evenly, if not you can warp the head, not easy to do but possible since it is aluminum. Try to richen (turn counterclockwise) the high needle a little, like an 1/8 to 1/4 turn to see if you can get rid of that engine stalling.

thanks!