perhaps i didnt phrase it right. it happens after 20 minutes, ground level dont matter, the vent hole could be clogged on the gas tank, and i did have to add a gallon of antifreeze to the radiator, the gas tank is near full.
kinda answering my own question, with this answer.. the gas cap aint vented, the tank comes with a small hole in it. a PITA too see. ya gotta take the tractor hood off.