My John Deere L130 will start but only run for a second. I can do this several times at full throttle and full choke and it only runs for a second or two. If I retard the throttle to 50% it will run a few seconds longer but that's it. I know this must be a fuel flow issue but the filter liooks good and the tank has been full since it last ran in October. The weather has been below freezing here in Atlanta on several occasions since it last ran.

Are you opoening the choke the moment it starts?

It will only start for a second with choke fully engaged. Once it starts, it doesn't matter what position the choke is in. You can leave it on full or try to feather it but the engine stops running after about a second. If you pull back on the throttle you may get 2 seconds but it always quits like the fuel is not flowing. I seems to fire off what is in the float bowl and then stop. Tank is full, intake tube in tank is unobstructed. There is fuel in filter but without an advanced manual or diagram, I don't know what to try past that point. From the fuel filter, the rubber line runs up to what looks like a small hockey puck shaped device with 2 other similar tubes running out of it. What is this and how does it work? It is mounted with 2 bolts but does not appear to have mechanical or electrical connection to engine. I don't want to mess with what I don't know because I tend to make problems worse.

Could be the fuel solenoid on the bottom of the carb , that's what it sounds like.
That hockey puck thing is the fuel pump , it's a vacuum pump could be bad , pull the hose off going to the carb from the pump see if there's gas , if so then look at the solenoid.
Luck

I tried to clean the ignition switch to solve my original problem (solved now) but put switch together wrong. There are three positions it can be assembled in and of course I was wrong the first two times. First time blew the 20 amp fuse, second time only a muted clicking sound from front of tractor which, thanks to you, I figure to be the solenoid. What exactly is it's function in the fuel supply scheme of things?
I will check all this out on Wednesday when it gets above 20... too dam cold to do anything unessential outside right now. I'll let you know what happens.
Thanks

I disregarded nothing sir. You need to open the choke immediately when the engine starts or open it after the first time it pops but hasn't started. I asked you a question, I gave no advice so I find you rating me a little silly. I was trying to gather more information to help you but I think I will find someone else to help. With 4 posts you onviously are new to the help desk but rating a question is not what the system was designed to do.

I tried to clean the ignition switch to solve my original problem (solved now). By not putting it back together right I heard a clicking from carb area when trying to start. What does solenoid do exactly?

It was designed to shut fuel off when motor was shut down ,to keep from shooting fuel in a hot cylinder , which in turn would cause a back fire,How ever if not working will not allow fuel into the carb as well
If you are here a clicking noise , sounds like its working.
What fixed the problem ?

I may have fried the solenoid while working out ign. Switch problem. May have held key in start pos. long enough to burn out solenoid contacts. Will disassemble and find location of solenoid. How can I check proper function? Any bypass method?

No bypass method
Replace or cut the tip off the needle