Put the air cleaner on it maybe running to lean with out it. Roger
Yes, holding the choke closed fixes it so I can flip the throttle back and forth between full and idle as fast as I want and it won't die. The new carb is a generic Nikki clone. It has one adjustment knob that I used to get it idling smooth and slow. The issue I'm tackling is that the engine will die if I increase the throttle. The new sparkplug made it so it's not as touchy. It went from ridiculously touchy to just very touchy.If holding the choke helps…presumably closed some. That means it is running lean(ie not enough fuel). Air filter will probably help, but either adjust the main jet open a little bit. Also you said the carb is new. Is it a Briggs carb or a chinesium carb? One last question, when opening up the throttle, are you sliding it up, or cracking it wide open?