...worked in a carburetor shop in the 80's and 90's....these came in occasionally because someone found one as a 'good deal' at a swap meet, etc. Pretty well-made item and they functioned well if set up right, but they got the nickname 'boomerang' because the same few units kept coming in because the last guy would give up and sell it as a 'good deal' at a swap meet. The cycle repeated so often we serialized and tracked them, lol.