Easiest way use a 3 line system ,fuel pickup line with clunk to the carb
one long enough to fuel with (then use a fuel plug to cap after filling)
the third to the nipple in the muffler then just a short piece on the crankcase
nipple out the bottom of the plane (vent). With the carb on the rear of a 4 stroke
trying to fuel through that is very unhandy. Really no different set up than a 2 stroke .