Picked this up from a friend that bought it for son, and son lost interest.
Got it running(new gas and plug), but it cant get out of its own way, fine at top-end, but from a stand still wont even go through grass. New gear oil and full, carb was cleaned(I will go through it again). The belt didnt seem like it was worn enough to slip, my 9 year old is not that big,this thing just has no power from the throttle. Any help

 

I don't know anything about this quad other than it has a CVT drive like mine (which is a GY6 4 stroke engine 150cc CVT drive). I'm thinking maybe you could take off the engine cover and look to see if the CVT drive belt is slipping. Else the clutch is slipping. This are the only two possibilities I can think of.

Check out this link:

Illustrated Parts List | amsportworks.com

It has downloadable service manuals which I think pertain to your quad...