RE: OS .40 FP
We don't have a listing for anything currently-made that may work. If you can measure the size of the neck of the carb that goes into the engine, we may be able to locate a current-production carb that may work. The carb for the .40LA may work, since the LA-series replaced the FP series:
OSMG2421 24081000 CARBURETR 40D 40/46LA US$24.99
It has a 10mm neck where it slides into the engine. This carb does use a remote needle.