I know nothing about this kind of stuff. But, when I started my weedeater, and put it on no choke (or even half choke), and gave it full throttle, it slowly died unless I let up on the throttle. I understand I should use 100% gas, but I Have E10 in this tank. I took the muffler off, and now it doesn't have this problem. Is there such a thing as a clogged muffler? How do I clean my muffler?
While I can't provide the technical details as to why, I would say your weedeater is performing as expected. With full choke and full throttle, you are flooding it when the muffler is attached. I would expect that you would smell or even see fuel coming out of the exhaust. However, with the muffler removed, the backpressure is so low that the engine can blow out more exhaust, so it continues to run, albeit with a different power curve (and lots more noise).
If you were experiencing power issues that are preventing the weedeater from performing its duties with the muffler on and choke off, then I would say there may be a problem.
However, for the sake of reducing noise pollution, I would encourage you to run your weedeater with the muffler installed.
What I did was I cleaned out the muffler with brake cleaner then blew it out with my air compressor (didn't really do much, I didn't see much carbon buildup come out). I put the muffler back on, dumped out the E10 gas that I had in the tank, replaced it with 100% gas, and now it works. Not sure which of these steps ultimately fixed it.
Ethanol requires less oxygen than gasoline. E-whatever will run rich and the choke will make it run richer. You don’t mention 2-cycle or 4 cycle, but if the former the muffler is an important part of the scavenge system. So you again change the mixture.
Mufflers running at full throttle tend to be rather hot and self-clean.