I hate to be a big cry baby, but we have had my sons new matrix for about three weeks. So far, the throttle servo has shorted out and smacked us into a fence, I have not been able to get this thing tuned so that it is crisp, and now I cant even get it to start and run. It dies as soon as you give it throttle. It is spitting fuel everywhere. I have pulled on that darn pullstart so many times that the one-way is starting to slip and the pullstart itself is about worn out not to mention that my forearm and fingers are about to fall off! I have tried every carb setting, including the one posted by Cen, and I am getting no results. I know you are thinking that it is too rich,which is exactly what it sounds like, but I have tried leaning it out until it was less than two turns out on the hsn and all that will do is prevent it from starting at all. Please dont think that I am just inexperienced. I have tuned a bunch of motors in the past couple of years but I have never seen anything like this. Also, I have tried replacing the fuel lines and tightened the seal on the fuel cap because I was seeing bubbles in the fuel lines but no help. Please help me, I am just about to give up on Cen motors.