I really do believe by the symptoms you are describing that there is a rev limiter by your description of how the quad moves out and then just levels out with alot of throttle left but unable to go any faster.

I don't have any experience with these kinds of limiters, but someone else on here should be able to help you out. I read on here all the time about people cutting a certain wire or adjusting a screw on the CDI to get rid of it. I'm sure that some people will jump in and give you some ideas and will be able to assist you in figuring out if your quad has this type of ignition.

 

I was just thinking, are you sure that the throttle is opening up all the way at the carb? The throttle cable sheath has to be stationary for the cable to open the carb slide. If the throttle cable is loose near the carb, then every time you press the thumb throttle wide open, the cable will move toward the carb instead of pulling the slide up in the carb. Just a thought.

 

yep, and Thanks.

Now I got a new set of problems....gas leaking,lol

 

OK then, back to the rev limiter opinion.

Do a search of this forum for float adjust. With the leaking gas, sounds like you may be a candidate for this.