If you choose to tap to a larger thread size, try a 6MM X 0.5. 7/32" is 0.218", and 6MM is 0.240". The 0.5 metric thread pitch is close to the same thread spacing as a 28 TPI thread in fractional measurements. a 1/4-20 would be too large, and too coarse a thread.
If you choose to re-tap, I'd suggest opening up all the other holes in that area of the carb to the same thread and replacing all the screws. That way there won't be any confusion caused by one oddball screw.
Jerry
