Hi my puch moped is having some issues. It starts on first kick (even when it's cold) and goes the full 28-30mph. The only problem is, it dies out really fast. When I put a little bit of fuel in it, it fires up, and can ride for about 10 miles. I know a moped can get like 80 mpg so I don't know what the beef is. Do you know what's going on? Thanks!