So I put my Troy-Bilt push mower with a Briggs and Stratton 725ex up for sale and before someone came to look at it I went to fire it up for the first time after winter. I've never had a problem with it but now it's not starting. The spark plug was pretty dirty so I went ahead and replaced it but nothing. Pulled the plug back out and it's dry as a bone. So I pulled the carb off. The bowl fills up, the float isn't sticking, the inlet tube is clear and the emulsion tube is clear. There's no reason it shouldn't be getting fuel. Any ideas?