I am new to this forum but I bought a ds 50 yesterday for my son, its a 2006 and I took it out today only to have the exact same problem. I found this site and went to work on the spark arrestor screen which was very plugged and I washed the air filter. So far so good it goes very good now, I started it without the restrictor and it definetly idled higher and ran good so I can see removing that in the future.