If fuel flow is only slightly restricted it can flow fast enough to keep up with demand for light or medium loads but when you are in the tall grass the governor is going to really open up the throttle and then the carb will eventually run out of gas with a restricted fuel flow. After sitting for a minute the carb will fill back up and it will start up again. Just cleaning out the sediment from the bottom of the bowl and draining the carb won't unclog anything. There could be a restriction in the sediment bowl inlet inside the gas tank, the sediment bowl screen, the screen in the carb inlet elbow, or the needle valve inside the carb. Some people have added an inline fuel filter and that could be a problem as well if you have one.