runs good, then bad, then shuts down

Congrats on using the TQ. Smart guy!

It sounds like flooding. If the carb has a lot miles on it, n/seats could be worn. They can also cause a higher float level. Anyway, they need to be checked. Usually you can remove the TQ airhorn without breaking the gasket. Another possibility is a 'heavy' float [ has absorbed petrol ]. A good nitrophyl float will weigh between 7.5 & 8 gms.