Rust in carburetor?

[climbstihl]

Ok, update: The saw is running now, I got lucky on the adjustment of tge metering lever, the stihl dealer told me he didn't have a gauge and to do it with a straight edge as said before, however, then it wouldn't start at all. I just bent the lever back up a bit, as I said, now I got lucky. The rust doesn't seem to be a problem. I now also went ahead and did my muffler mod. I also had the isdue before that I couldn't get the chain to stop at idle without turning the LA all the way out, that is gone now.