I just gone changing my oil and when I was done and turned the scooter on to run the new oil through, the scooter started very shaky and then after I gave it a little gas, it got itself to go up to 20 mpg. I thought it was going to continue to go faster so I turned it off. I let it sit for a half an hour or so and started it up again and it ran high again. I tried driving it to see if that would stop it but it didn't. I got back home and was unable to back up the scooter with it still running. I had to turn it off to back it into the garage. I wasn't sure how to look this problem up in other forums. Any ideas? Thanks in advance!