Small Engines (Lawn Mowers, etc.): John Deere riding mower, gravity feed, circular piece

Question
My Father in law's mower will not start. I noticed down stream of the fuel filter there is a small (black) circular piece that the fuel line goes through. Is this a fuel pump? If it is should it pump fuel when I try to start the engine?

Answer
Cliff,

   Generally a model Of tractor helps Determine your Answer However Smaller JD tractors Do not Have a Fuel Pump It is all gravity feed fuel systems the small Black circular Piece May be just a Clamp for the hose to Port fitting If you Can get me a Model Series I can furthur diagnose a better answer to you.
But If it is getting Fire thru the Spark Plug and you have compression and you can smell fuel thru the Plug port you Know it should turn over But take away just one of the components and it wont run check to make sure your getting spark remove the plug and set it on a Engine Bolt and try cranking it If you see a dark bule white spark your good there Put your thumb over the hole and crank it to see if it has strong compression If it tries to push air past your finger you have great compression If when you smell in the hole you smell gas then it is getting fuel .
with a Model Number we can furthur diagnose this issue try what i suggested and if it does not work then we can go from there.
Make sure the spark plug is cleaned of all carbon this improves the Spark output