1. Check the fuel tank vent filter to see if the tank is venting properly. (could just take the cap off and see if it will start better).
2. Check the prefilter (strainer) at the bottom of the tank to see if it is plugged. Make sure fuel is flowing freely through this.
3. Call John Deere.
What ever it is you will want to get it fixed and not starve the HP pump for fuel because that will get expensive.
John