Thanks for keeping us posted Greg. I can't see a blockage in the picture. As a rule of thumb though, if a muffler is a lot heavier than it used to be, it's time to do something about it. People use different methods for cleaning them out - cook them then tap them on something, burn them out by sustained full load and full throttle, even cut them open and weld them up afterward. Aside from getting the engine to run properly again, the main test is what they end up weighing compared with a new one.
