Had my carb off 4 times, not wanting to remove the "TINY" brass plug under the Large high speed needle, in the bottom of the carb bowl, afraid that I would break/destroy it. After I removed it and blew the bowl out well. Re- assembled/installed the carb. It has run like a champ. Couldn't believe it was so simple. Hope this works for you. I also added an inline fuel filter to keep out any possible fine dirt.
Owner of a 1957 310, Backhoe/Loader, almost completely redone.