I bought a gas engine at the Perry, GA swap meet two years ago. I believe it is a US engines 23 or 25cc. Name plate says USE Engines, Syracuse, NY, Model No. 257951, Serial No. 004786. USE Engines doesn't exist anymore. Engine has a walbro carb and runs OK. My problem is that I broke the piston ring while cleaning it and need another. I am having a hard time identifying a parts source. Piston diameter is approx 1 and 9/32" in diameter. Does anyone have a suggestion as to how to proceed? Thanks much.