At first I was thinking it sounded like a fuel flow issue, but I think that would be come with some engine stuttering. It is likely a carb issue if the machine has been sitting idle for any length of time. If you are comfortable doing it, I would open up the carb and give it a good cleaning and inspection. Use lots of carb cleaner, soak the jets, and use firm toothbrush to get all of the shellac off. Blow carb cleaner and air through all of orifices in the carb body. The wire inside of a bread twist tie is smll enough to fit through most jets, and soft enough to not damage the brass.
Also check that the air box, air intake runners, muffler, and spark arrestor screen are unobstructed. Here in Michigan, it is common to find mouse nests, and chipmunk nut caches in airboxes and tail pipes.
What does the spark plug look like? The color and condition of the plug can help to diagnose the issue.
https://ngksparkplugs.com/en/resources/read-spark-plug Good luck!
