That is so strange you post this because I have a Janome 6019 and have just started smelling a burning smell the past few weeks and wasn't sure where it was coming from.
Is your foot pedal getting hot-is that how you know it is the pedal??
I have to work my foot/ankle very carefully to moderate the speed of my machine to get a steady medium speed. I also seem to have power serges as well and that will make the machine go "postal fast" all the sudden (that I believe is related to the electrical wiring in the room I am using).