I have a 2007 hammerhead 250 ss go kart that I just put a carb on due to a rough idle. But with the new carb it reves way higher and if only went for 4 20-30 minute rides once I am done I always shut it off then restart it for rides 1-3 it started right back up but on the forth ride it didn't want to start and at the end it stated spudering so I put it away and shut it off. Also since it is winter I didn't use my fans which I had to put on a swich becuse they broke. But for some strange reason I am concerned and scared that because,it is reving much higher that maybe it causing engine damage. But what I want to know is should I not rev it as high and should I use my fans I really want to know before I blow it up because that would be expensive.