Dude when an engine is in the break-in state and you give it the gas and it dies you do NOT want to richen the high speed. If you've already got a few tanks through it then you can lean the low speed a tad and the high speed as well. This should allow you to start reving the engine a bit faster. If you richen the highspeed you'll just make it die even faster because more than likely its dying because its super rich and is flooding out.