Generally some fuel will come into pressure line when tank becomes full. However it should not flood engine since it shouldn't be getting into carberator then into intake unless needle valve is wide open or if engine is inverted then it could flood motor from muffler. Anyway no reason that excess fuel can not be worked out prior to connecting glow starter. If it is starting and only running few seconds perhaps needle valve is wide open and engine floods soon as it starts. Close needle valve completly, open just 2 turns. Assuming it not now flooded hold finger over carb intake and turn over prop about 3 times(without glow starter on). from then it should start. Repeat if need be. Once it starts adjust needle for rich running (open about 1 turn). If not getting success get some help from expert.