When i bought my new kart the guy i bought it from started it up. It wouldnt idle which i beleive to be a carb prblem. He said the starter has a new battery. I started it one time with the starter and it ran for a little bit but once i let off the throttle it died. I tried starting it a few days later and it seemed like the starter wasnt turning it as strong as it used to and the engine wouldnt even turn over. I took it to get it tested and charged and they said the battery was good. Tried to start after charge and it worked once then went back to not being able to turn the engine over. Any ideas?