225 stalling

I'd look at the carb .The float height . It may have picked up a small particle in the fuel and have a clogged jet .Take it all apart and squirt carb cleaner thru all the passages and jets . Could also be an issue with your points or a failing condenser or a failing coil . Could be a bad spark plug wire or corrosion in the cap where the wires plug in
Carb is super clean, only issue is that messed up o ring on fuel intake, swapped with what I have on hand. I've found that if I hold the choke about 90% closed it idles perfect but need to open choke as I accelerate. So I assume it's a fuel delivery issue. I suspect the o ring is at fault or a failed pump