Coleman powermate 6250 generator will not start

Question

About a year or so ago, I purchased a Coleman Powermate 6250 premium pus 5000 watt generator from an individual. It has remained in the original unopend box until today. I added fresh fuel and SAE 30 oil and attempted to start it. Nothing -- seems as though it is not getting gas. I checked the shut off to ensure it was in the correct position and even pulled the hose to verify. I also loosened the fuel bowl and as I did gas poured out -- so there is gas at least there. I sprayed starter fluid into the carb and it will fire up for a few seconds and the shut off agin. The engine is a Briggs and Stratton 10 HP OVH. The manual is pretty much useless -- has no trouble shooting tips at all. Any help is appreciated!!

Harold