Certainly sounds like a low fuel flow issue. It would not hurt to run some cleaner through in the fuel while it is running. Some small carbs have a diaphragm that can get stiff and not deliver enough fuel.
It's not low fuel. When I run the lawnmower, I run it topped off. By the time the lawnmower stops working, it's gone down maybe 1/4 (so, 3/4 full) and I have to add more fuel to the take to "push" fuel into the carburetor.
This issue was present in my old carburetor before rebuild, old carburetor after rebuild, and completely brand new carburetor.
Keep in mind that 10% ethanol gas can eat a hole in a plastic line.
There are no fuel leaks anywhere.