Riding Mower Dies After Starting?

I have a L118 John Deere/22hp twin V OHV riding mower that just gives me grief every time I sit on the danged thing. When I first turn the key the fly wheel takes off as normal, but before the engine actual starts in dies down to nothing. I replaced the battery, terminals are clean, new fuel, and fuel filter. Any suggestions on what is going on?

By Robin V.