A new spark plug, or at least a clean one that fires, is a good idea Rich. However, I would say it is 90% likely to be the carb.
Modern petrol turns into a gel and then crystalises, blocking the fine orifices in the Walbro/Zama type carbs. Also, Chinese diaphragms harden relatively quickly unlike the original Japanese ones - they use poor quality rubber. I would strip it down completely, remove all the gaskets, diaphragm, mesh filter screen etc. and blast all the orifices with carb cleaner.
Then rebuild with a new diaphragm kit.
It's a simple job provided one marks all the components to indicate positioning/orientation and preferably takes photographs during disassembly.
There are lots of good "how to" guides on Youtube.
https://www.youtube.com/watch?v=cDaOcNrS6BM
https://www.youtube.com/watch?v=EKXwoP9Pa1U