first thing to do is check flow properly by taking out the drain screw on the carb bowl and watching fuel flow for a while (I use a cut off piece of funnel to flow it into a jar)
you may find that it flows well, then stops which usually means that the air vent in the gas cap isn't working (take gas cap off and see if it flows)
gas cap can be drilled to make a new vent hole
if not the cap, then check both fuel filters for clogs
Sometimes I sets and thinks, sometimes I jes sets.