Yes everything said above...if everything upstream is dirty have to clean it all or bypass for testing.
Starting fluid burns very hot and can do damage if used too much. Best to put a little gas in plug hole. If machine hasn't been started for a long time I use gas for 2 cycle so there's some lubrication. Haven't heard too many good things about aftermarket carbs, well worth cleaning the original carb.
I have a gallon carb clean can with a basket to soak disassembled carb for a hour then into heated ultrasonic cleaner for how ever long it takes. I look at all small holes/jets through a loupe until I'm satisfied and then blow out with compressed air. There are small holes in carb throat as well that have to be open. There are breakdown's of the carp parts online which is handy especially if someone has taken apart before you. New jets and most carb parts are inexpensive if needed.
Lots of info on carb cleaning but that's how I do it.
Pics of a 68 CT90 carb