318 scamp was strong now barely responsive

Check for dirt or water in the carb / filter. This is why you dont fill up while the tanker is dropping gas in the tank at a gas station. It stirs up the crap in the bottom of the tank.
From what you described, this is where I would start.

I once got the filter wet in my 70RR (440-6 air grabber) and it was AMAZING how much more power it made with the filter out LOLOL)