Dirty, it's quite difficult to describe the lever adjustment. There are several good YouTube videos showing rebuilding of Walbro carbs. I think watching a few of those videos would really help. On a side note, dirt in your internal filter screen was not a result of your accident. This is debris that is coming in from your fuel system. Those links loaded funny. Click on the times to get to the videos.
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www.youtube.com/watch?v=K5C86ZYNcnI
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www.youtube.com/watch?v=RfzzTilqwo0