My John Deere L110 Riding Mower all of a sudden has decided not to start. I turn the key and it cranks, but does not start. By looking at the fuel filter, it appears there is no gas in the filter. I have verified that the fuel line is flowing well and that there is gasoline in the tank. The engine has been serviced recently including a new spark plug.
It's clear to me that you have identified the main cause of this: Fuel is NOT getting into the engine.
You noted that there doesn't appear to be any fuel in the fuel filter, so the next step is to determine WHY that is the case.
Is there a fuel shut-off valve?
Is there a fuel screen that is blocked?
Is the fuel line pinched or clogged?
What about the carburetor? If it's clogged it will prevent fuel from flowing. If the float it stuck that will also block fuel from flowing.