A curious issue.The 'autostop' on a pump nozzle is triggered by the end of the nozzle being immersed in fuel (it covers a small tube that runs inside the main delivery tube which is constantly 'sucking'. As soon as it is unable to 'suck' it shuts off the valve in the handle). The fact that you can overflow the fuel tank filler pipe without fully covering the whole nozzle tip would suggest that maybe the nozzle tip isn't in far enough, or is too horizontal so that fuel can flow back and out underneath the nozzle, or something else that is preventing the nozzle from being immersed. As with others - I always have the other problem and have to find the right position to prevent it auto-stopping constantly.