Mower stops running after I've been mowing for about 30 minutes. I changed the spark plug and fuel filter. It seemed to work and I was mowing the lawn then it just started acting like it was running out of gas unitl eventually stops.

Take the fuel bowl off and clean then clean the fuel jet. a partial plugged jet will do this. could also be the float in the carb is sticking shut so could need cleaning as well. Would do good to run fuel cleaner through a tank of gas to clean things up. This is just an idea but worked for me.

The fuel tank breather is in the fuel filler cap, run the machine with the filler cap loose to allow air in, if the tractor runs ok, then replace with a new cap.

Interesting! Try seeing if it will run without the fuel tank cap on. There is normally a small hole to let air in as fuel is used, if this gets blocked the fuel will stop running from the tank. You probably won't be able to clean it well enough so a replacement cap shouldn't be too expensive.

Ignition module is failing

try running it with the gas cap loose the vent might be plugged

HI
suggest : check spark plug or renew / weak fuel mixture /
insure / air vent hole is clear on fuel tank cap

Try this.
When the mower is about to die, loosen the gas cap.
My mower gas cap vent holes plugged up and kept stalling the mower.
If it works, drill out the vent holes.
Gary

Troy, Unless you are using old fuel (it breaks down after 1 week) it sounds like you have a faulty spark plug. Replace this first, drain any old fuel and replace with fresh fuel (premium unleaded). A faulty plug will work one minute but then fail like you have described.

Remove the air breather filter, it might be dirty. Stephen.

It can be quite a things - a blocked air filter or a blocked exhaust. To clean the exhaust, unbolt it from the manifold, hold it vertical and hit on the side until no more soot comes out. Changing the air filter should be pretty straightforward. If the spark plug bottom end is black then you have the fuel mixture too rich and you should lessen the flow of fuel.