Another aid to safely loosening carb stuff....putting the carb body or jet block into the freezer for 15-30 minutes, followed by immediate dunking into pre-heated ultrasonic bath. Cold contraction/ heat expansion creates some sort of magical scenario....frozen jets more apt to removal, clogged circuits more apt to clear with less need for super aggressive efforts.
https://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html May be worth a try, but as the coefficients of thermal expansion for brass and alloy are similar it is less effective than other metal combinations. That’s one of the reasons for using this combination of metals in carbs.
only just seen this - offending brass screw is often fractured and close to breaking off - I remember warning someone of the very same thing over 5 years ago on here.. From memory, it's only hollow to allow full stroke of needle. Have often found them replaced by a steel screw hollowed out, stainless would be best. The original screw wasn't really man enough for the job in brass particularly when hollowed out.
