Following Duffyjr comment, are there stronger in tank cleaners that might dissolve any blockage? I'm guessing (completely) that some type of particle maybe lodged in one of the jets?
Putting something in the fuel to open-up a plugged jet won't work. The jet has to be open for something to be able to flow through it. In your case, it is likely a piece of dirt/sand that is plugging the jet. No additive will dissolve this anyway.
CT8, it does have a float bowl drain screw. Will try this bowl drain first - very good idea. Beyond draining the bowl, what if I used some gentle air pressure and blew it into the drain hole?
The float bowl is vented. Blowing air into it by any means won't open-up a plugged jet.
No way around it, the carburetor is going to have to be disassembled and the jets manually
cleaned. 95% of the time you won't need a carb kit or gaskets other than sometimes a carb to intake manifold gasket. The float bowl will have an o-ring or rubber gasket. Once you have poked through all of the jets, spray carb cleaner though all of them, and the idle circuits, to make sure they are clear. If you are not comfortable doing this yourself, take it to a shop and pay to have it done.