Could be a bad regulator or crud in the carb or fuel line. I would use a filter just before the regulator and clean out the carb, then set the fuel to 6psi set your floats and see what happens
Could be the regulator, the carb was just rebuilt. I have a 100 micron filter after pump, 1/2 in line into pump then into regulator. Fuel line is new too.
Going to buy new fuel regulator, Quick Fuel, it's pre set at 6.5 psi and then re adjust everything and see what happens!
