Echo 266 wont run

I have a Echo SRM-266 that was running real rough. So I ordered an official Briggs and Stratton carburetor and spark plug. Bolted up the carburetor and it didn't seem to get all the power it should, so I turned the screw on the top of carburetor and tried to get it to run smoother and more powerful. Did no help. My first question is there are a couple gaskets that go between the covers and carburetor. Would like to see a drawing of which way they go and in between where..
Then any other information to get it running strong again would also be helpful..Abit lost..
Thank you
Dean

I ordered carburetor only for the echo SRM-266. I am not sure where the gaskets go, outside of the carburetor, when mounting, and which way is up - as the gaskets can be flipped 180 degrees very easily. Those drawings doing show it.Does someone have one that is working, that can look at how theirs is put together?  Gasket then plastic, or gasket in between the plastic pieces on both sides???  Which way does the gasket go, as it to can be installed up side down and not.