my whipper snipper will only run on half choke?

I have a ryobi whipper snipper model PLT3043A
I have replaced the fuel lines and can run the machine on half choke but as soon as I go tonormal running I get a slight surge and it dies. If I quickly move back to half choke it's ok but not running at optimum revs.

I haven't played with anything there are two plastic adjusters I think Red and white .The lug on the red is pointing down and the lug on the white is pointing across
the top of the red.
Are these adjustable? or is there something else .

Any info will be greatly appreceated (spelled that wrong)

Thanks guys looking forward to your replies