Hey Wally-
I think that it would not work at all. I think that it would hold the butterfly closed because it's in backwards and as it heated it would try to close it further. Once it heated, I think it would run okay, but when it's cold, it would run rough. I could be wrong, and I'm sure someone else who has more experience will come along and give you a better answer, but if the spring is in backwards, I think that is what would happen.
Mark
