I have a John Deer Riding Lawn Mower LX 173. It won't start. It ran fine last fall and I have a new battery on it. It will start with the help of starting fluid and run for just a second and then shut off. I found a hose disconnected on it but I'm not sure where it goes. It was laying near the seat (underneath). I'm not sure if it even goes to the lawnmower because I didn't see a place for it: :confused:

I purchased a new spark plug (should I put it on?)
It acts like it's not getting gas. Could it be the carburetor? Maybe it's out of adjustment?
How do you adjust that screw?