JD Z255 zero turn

[Coachvb]

My mower runs fine for about 20 minutes then starts revving intermittently and shuts down. I let it sit for a while and start it up again, it has started right up, and it does it again. I have changed the spark plugs with no change. Yesterday and today it only runs for about 5-10 minutes and it was hard to start. Any suggestions?

 

[bertsmobile1]

Pull the fuel line off the fuel pump, remove the fuel cap and blow backwards up the fuel line.
If it gets better you have a fuel blockage in the fuel tank.
For fuel to get out, air has to get in and the air behind a ride on is very very dusty.