I tried with a plugged outlet on the pitts and nothing changed. I finally tried it with the stock muffler on a test stand and WOW, the engine came to life. Top end improved by almost 200 rpms with a smoke trail coming out which means it is running rich.

Now my only options are to run the engine inverted or get some sort of muffler extension. I think mounting it inverted is the best option at the moment.