my tractor was running badly, missing like it was starving for fuel. i looked in the fuel tank, down but not empty. i refueled the tractor, topped it off. i had a 6 gallon fuel can almost full. when i was done fueling the fuel can was still about 1/2 full...... probably put 2.5-3 gallons in the tank. the tractor runs as it should again. how do we explain this? i know the tractor is supposed to have a fuel capacity of 6.6 gallons, if it really truly was running out it should have swallowed the entire can and wouldn't be completely full. what gives?