My mower will start and run for a few minetes then stops

Do you have the bowl type card ior the diaphram where the gastank sits on the carb? If the bowl type remove the nut on the bottom of the bowl. This is the main jet. Run a small wire through the holes. Also check the bowl for dirt and debrit.
Troy

Did you try cleaning the carb/check fuel filters? I would try this first.
Does it sputter before it dies or does it just die as if you hit the killswitch?.