I just purchased my first Vespa (1980 P125x) Starts on third kick cold. Seller says he just rebuilt the engine and it seems to run pretty strong.
Problem is after I run about 5 blocks it tries to die. There is a flat spot when first twisting the throttle then it picks up. In the event the scooter does die it most likely will not start when it is hot.
I have drained fuel and put in new, installed a new properly gapped plug, and cleaned out the carb. It acts like maybe it is running rich and loading up. I hate to mess with the mixture tho.
Any help is appreciated. I have no known Vespa mechanics in the area so it’s just me, this forum and my Haynes manual.