Looks like your engine is running a little warm.
Fun-Loving Maniac Blasts Jet-Powered Go-Kart To 90MPH While Steering With One Hand

Because some people still believe in a having a little dangerous fun (the best kind), this is a video of “Rocketman” Robert Maddox blasting around a dried lake bed in “The Beast”, a pulse-jet powered go-kart he built. In the clip he hits speeds up to 90MPH while the engine glows devil red behind him and a propane tank and he steers with one hand, filming himself with the other. Rocketman says this was only at about half throttle too, since he didn’t want to open it all the way up with only one hand on the wheel. Hey — safety first. Or may third or fourth in this case.