I got the redcat mpx 50. and never changed the plug and its got atleast 100 hours on it and started running goofy. and I know I have seen the crossover plug but now I cant find it. anyone remember?????? thanks

 

NGK C7HSA Try that first, if it still does it & the carb is clean, it most likely needs a valve adjustment after that many hours. They should both be set at .004 at Top Dead Center.

 

is the T.D.C. marking under the valve adjust cap?

 

No, on the left side of the engine there should be a small screw on top remove that & the one on the side the bigger screw cap & turn it over by hand with a 17mm, then just find the timing mark on the magneto & it should be at TDC by looking through the top screw cap hole you removed.