Esante feed dog problem

Question

I have a esate i have checked the feed dog and it seems the white shaft that holds the feed dogs up is not doing it's job it seems to look fine on the shaft i can hold them up with a scredriver and they are about a fourth aof and inch away from the shaft that holds them up the s***w seems tight as i can't turn it with a scredriver do i need to maybe raise that s***w up so it is touching that white piece the cam looks good no knicks or anything i can see plese help..