Changed oil, oil filter, air filter, and spark plug. Stalls constantly, I believe it's some left over gas causing the issue, wasn't run out as I thought for the winter season. Is this the fuel filter, if so where is that? What else might be causing the issue?

Check fuel filter if there is one. Also check vent hole in gas tank cap.

I'd drain out the fuel from the tank and the carb bowl. Old fuel stored over the winter can have condensation in the gas.

What is the device that the fuel line from the tank leads into? From this it has a line leading to mix with the oil (it appears to do this, I could be wrong), and another line leading to mix with the air. Could this be causing the blockage as it is the only thing I haven't been able to clean out?