I have parts from an old carburator that might have come from an old OS 40SF, but I am not sure. Does your needle valve look like this?
The carburator is a little rusty but the needle valve looks in good shape. The letters molded on to the front of the carburator say ''AA''.
Will this do?
That's an Air bleed cab,, would have come from a FP,, not a SF,, SF carbs have a low end needle
I'm pretty sure you want a 4D carb for the 40-46sf