Bill, A Marconi sloop would look funny in a class IV rapid, still, I'll photo it if you'll sail it.
Anyway,,,,I do have a Sullivan Crap trap between the tank and the pump. I flushed the carb at the field but not the pump. I'll try that next.
I lost my pitts muffler last week but replaced it with the exact same model. Could the muffler be different somehow? I doubt it, but you never know.