From my experience with this engine it is a set it and forget it kind of engine. I would get back to basics and start by checking your sensor position and high and low needles. If these are OK..look at your fuel system to make sure you don't have any obstructions or loose fittings. It is a good practice to put some holes in your motor box so the carb can breath. I usually put one or two 1/2" holes in the sides and bottom of the box. The top has a cover that is screwed on. Getting back to the engine make sure that your throttle butterfly is turning the right way and that everything is tight. I usually set my low needle first, then peak the rpm and back the high needle off a little on the rich side. Once this is done you don't really need to fool with it. I wouldn't stress myself out over it. If you still can't get it to work right box it up and send it back to RC Showcase. For a small fee they will get it running good as new.