do you have alot of blue smoke coming out of the pipe? you may be running the high speed needle too rich. If you have smoke coming from the glowplug hole, then it is too lean. To richen the mix,turn counter-clockwise.To lean the mix,turn clockwise. you may also want to check the low-speed needle, just make sure that when you turn a needle...do so in small increments. I would also recommend to call traxxas or check out their troubleshooting section on
www.traxxas.com good luck