Star the engine and run it about 30 seconds, then shut it off. There is a fuel shutoff at the filter bowl; turn it to shut the fuel off. Use channel locks to loosen the ring at the top of the filter bowl, then pack rags down on top of the flywheel guard to catch spilled fuel. Unscrew the ring and pull lightly down on the bowl. The filter will stay in place. Empty the bowl, remove the spring and water ring and clean the bowl. Pull down on the filter to remove it, and push the new filter in its place. Make sure the spring and water ring are in the bowl, then slip it up over the new filter. Thread the retainer ring hand tight, then snug it with the channel locks. Open the shutoff valve and let the bowl fill as much as it will. There should be some residual fuel pressure in the line.
Start the tractor, It will fire and run, then begin to stumble. It may or may not quit. If it quits, keep the throttle about 1/2-3/4 open and continue to crank for a few seconds at a time, it will eventually start, maybe run rough for a few seconds, then smooth out. The injector pump on these engines is self-priming, no need to loosen anything to bleed air.