Originally Posted by Sapperwhite
Agreed, Seloc has a way with words to help you understand your motor. I would recommend it over any others.
If choking it keeps it running it does sound starved for fuel. Float valve can stick or stuff can block flow even if the float and valve operate correctly. I had a head gasket leaking water into the combustion chamber on a 2 HP older motor and with choke on it would at least run. The evidence was in removing the spark plug and shining light on the piston to observe tiny droplets on the piston. Very little water, but gasoline will generally not leave this evidence so I replaced head gasket. The gasket gave me even better indication where the leak was.
Lastly, if the float or valve were not filling the carb bowl with gas due to sticking would expect a shot of starting fluid while it falters would bring up the rpm as the fuel shortage would be remedied and the intake path wouldn't be blocked. Hope this helps and let us know what you find.