My BX23S had 'fuel problem' ,6 years ago. ran fine, then rough, then  yeesh hope I make it hope.....
'Something' was plugging the spigot. Took a leisurely day to remove tank, finally found the culprit. A small, black, sliver of plastic was plugging the spigot ! Now there it NO way I'd been able to see that( black on black is very hard on my eyes) and it was DOWN into the spigot. Compressed air blew it out and into the tank, several flushing with water and it finally came out...now sitting by my computer monitor. After reassembling 'Humpty Dumpty', I added a 'cold coffee mason jar filter' for $20. ZERO fuel issues since ( +-1000 hrs ). BTW get a helper to remove/install the seat and the floor pan. Both are miserably difficult if you're a senior !