Those type of pulley can be the hardest to remove. I have in the past had one glowing red! It still wouldn't budge and had to cut it off with an angle grinder. Unfortunately because they are pressed tin there is nothing solid to pull with. A nut on the bottom may well be you're best bet. Personally I have never seen a grub screw on a pressed tin engine pulley.
Weld a nut on the bottom so you have a solid point to apply pressure, then soak in inox or wd, then apply heat..
These pulleys are usually one extreme or the other, I have also had them fall off when undoing the crank bolt. depends on how much moisture got in there.
